Deploying Ceph with TripleO

In Wallaby and newer it is possible to have TripleO provision hardware and deploy Ceph before deploying the overcloud on the same hardware.

Deployed Ceph Workflow

As described in the Networking Version 2 (Two) the openstack overcloud command was extended so that it can run all of the following as separate steps:

  1. Create Networks

  2. Create Virtual IPs

  3. Provision Baremetal Instances

  4. Deploy Ceph

  5. Create the overcloud Ephemeral Heat stack

  6. Run Config-Download and the deploy-steps playbook

This document covers the “Deploy Ceph” step above. It also covers how to configure the overcloud deployed in the subsequent steps to use the Ceph cluster. For details on the earlier steps see Networking Version 2 (Two).

The “Provision Baremetal Instances” step outputs a YAML file describing the deployed baremetal, for example:

openstack overcloud node provision \
        -o ~/deployed_metal.yaml \
        ...

The deployed_metal.yaml file can be passed as input to the openstack overcloud ceph deploy command, which in turn outputs a YAML file describing the deployed Ceph cluster, for example:

openstack overcloud ceph deploy \
        ~/deployed_metal.yaml \
        -o ~/deployed_ceph.yaml \
        ...

Both the deployed_metal.yaml and deployed_ceph.yaml files may then be passed as input to the step to “Create the overcloud Ephemeral Heat stack”, for example:

openstack overcloud deploy --templates \
        -e ~/deployed_metal.yaml \
        -e ~/deployed_ceph.yaml \
        ...

While the overcloud is being deployed the data in the deployed_ceph.yaml file will be used to configure the OpenStack clients to connect to the Ceph cluster as well as configure the Ceph cluster to host OpenStack.

The above workflow is called “Deployed Ceph” because Ceph is already deployed when the overcloud is configured.

Deployed Ceph Scope

The “Deployed Ceph” feature deploys a Ceph cluster ready to serve RBD and CephFS by calling TripleO Ansible roles which execute the cephadm command. When the “Deployed Ceph” process is over you should expect to find the following:

  • The CephMon, CephMgr and CephOSD services are running on all nodes which should have those services as defined by the Deploying with Composable Services interface

  • If desired, the CephMds and CephNFS service will also be deployed and running (this feature is not available in Wallaby however).

  • It’s possible to SSH into a node with the CephMon service and run sudo cephadm shell

  • All OSDs should be running unless there were environmental issues (e.g. disks were not cleaned)

  • A ceph configuration file and client admin keyring file in /etc/ceph of overcloud nodes with the CephMon service

  • The Ceph cluster is ready to serve RBD

You should not expect the following after “Deployed Ceph” has run:

  • No pools or cephx keys for OpenStack will be created yet

  • No CephDashboard or CephRGW services will be running yet

The above will be configured during overcloud deployment by the openstack overcloud deploy command as they were prior to the “Deployed Ceph” feature. The reasons for this are the following:

  • The Dashboard and RGW services need to integrate with haproxy which is deployed with the overcloud

  • The list of pools to create and their respective cephx keys are a function of which OpenStack clients (e.g. Nova, Cinder, etc) will be used so they must be in the overcloud definition. Thus, they are created during overcloud deployment

During the overcloud deployment, the above resources will be created in Ceph using the client admin keyring file and the ~/deployed_ceph.yaml file output by openstack overcloud ceph deploy. Because these resources are created directly on the Ceph cluster with admin level access, “Deployed Ceph” is different from the “External Ceph” feature described in Use an external Ceph cluster with the Overcloud.

The main benefits of using “Deployed Ceph” are the following:

  • Use cephadm to deploy Ceph on the hardware managed by TripleO without having to write your own cephadm spec file (though you may provide your own if you wish)

  • Focus on debugging the basic Ceph deployment without debugging the overcloud deployment at the same time

  • Fix any Ceph deployment problems directly using either Ansible or the Ceph orchestrator tools before starting the overcloud deployment

  • Have the benefits above while maintaining hyperconverged support by using a tested workflow

In summary, openstack overcloud ceph deploy deploys the Ceph cluster while openstack overcloud deploy (and the commands that follow) deploy OpenStack and configure that Ceph cluster to be used by OpenStack.

Multiple Ceph clusters per deployment

TripleO can only deploy one Ceph cluster in the overcloud per Heat stack. However, within that Heat stack it’s possible to configure an overcloud to communicate with multiple Ceph clusters which are external to the overcloud. To do this, follow this document to configure the “internal” Ceph cluster which is part of the overcloud and also use the CephExternalMultiConfig parameter described in the Use an external Ceph cluster with the Overcloud documentation.

Prerequisite: Ensure the Ceph container is available

Before deploying Ceph follow the Container Image Preparation documentation so the appropriate Ceph container image is used. The output of the openstack tripleo container image prepare command should contain a line like the following:

ContainerCephDaemonImage: undercloud.ctlplane.mydomain.tld:8787/ceph-ci/daemon:v6.0.0-stable-6.0-pacific-centos-8-x86_64

See “Container Options” options below for more details.

Prerequisite: Ensure the cephadm package is installed

The cephadm package needs to be installed on at least one node in the overcloud in order to bootstrap the first node of the Ceph cluster.

The cephadm package is pre-built into the overcloud-full image. The tripleo_cephadm role will also use Ansible’s package module to ensure it is present. If tripleo-repos is passed the ceph argument for Wallaby or newer, then the CentOS SIG Ceph repository will be enabled with the appropriate version containing the cephadm package, e.g. for Wallaby the ceph-pacific repository is enabled.

Prerequisite: Ensure Disks are Clean

cephadm does not reformat the OSD disks and expect them to be clean to complete successfully. Consequently, when reusing the same nodes (or disks) for new deployments, it is necessary to clean the disks before every new attempt. One option is to enable the automated cleanup functionality in Ironic, which will zap the disks every time that a node is released. The same process can be executed manually or only for some target nodes, see cleaning instructions in the Ironic documentation.

Deployed Ceph Command Line Interface

The command line interface supports the following options:

$ openstack overcloud ceph deploy --help
usage: openstack overcloud ceph deploy [-h] -o <deployed_ceph.yaml> [-y]
                                       [--skip-user-create]
                                       [--skip-hosts-config]
                                       [--skip-container-registry-config]
                                       [--cephadm-ssh-user CEPHADM_SSH_USER]
                                       [--stack STACK]
                                       [--working-dir WORKING_DIR]
                                       [--roles-data ROLES_DATA]
                                       [--network-data NETWORK_DATA]
                                       [--public-network-name PUBLIC_NETWORK_NAME]
                                       [--cluster-network-name CLUSTER_NETWORK_NAME]
                                       [--cluster CLUSTER] [--mon-ip MON_IP]
                                       [--config CONFIG]
                                       [--cephadm-extra-args CEPHADM_EXTRA_ARGS]
                                       [--force]
                                       [--ansible-extra-vars ANSIBLE_EXTRA_VARS]
                                       [--ceph-client-username CEPH_CLIENT_USERNAME]
                                       [--ceph-client-key CEPH_CLIENT_KEY]
                                       [--skip-cephx-keys]
                                       [--ceph-vip CEPH_VIP]
                                       [--daemons DAEMONS]
                                       [--single-host-defaults]
                                       [--ceph-spec CEPH_SPEC | --osd-spec OSD_SPEC]
                                       [--crush-hierarchy CRUSH_HIERARCHY]
                                       [--standalone]
                                       [--container-image-prepare CONTAINER_IMAGE_PREPARE]
                                       [--cephadm-default-container]
                                       [--container-namespace CONTAINER_NAMESPACE]
                                       [--container-image CONTAINER_IMAGE]
                                       [--container-tag CONTAINER_TAG]
                                       [--registry-url REGISTRY_URL]
                                       [--registry-username REGISTRY_USERNAME]
                                       [--registry-password REGISTRY_PASSWORD]
                                       [<deployed_baremetal.yaml>]

positional arguments:
  <deployed_baremetal.yaml>
                        Path to the environment file output from "openstack
                        overcloud node provision". This argument may be
                        excluded only if --ceph-spec is used.

optional arguments:
  -h, --help            show this help message and exit
  -o <deployed_ceph.yaml>, --output <deployed_ceph.yaml>
                        The path to the output environment file describing the
                        Ceph deployment to pass to the overcloud deployment.
  -y, --yes             Skip yes/no prompt before overwriting an existing
                        <deployed_ceph.yaml> output file (assume yes).
  --skip-user-create    Do not create the cephadm SSH user. This user is
                        necessary to deploy but may be created in a separate
                        step via 'openstack overcloud ceph user enable'.
  --skip-hosts-config   Do not update /etc/hosts on deployed servers. By
                        default this is configured so overcloud nodes can
                        reach each other and the undercloud by name.
  --skip-container-registry-config
                        Do not update /etc/containers/registries.conf on
                        deployed servers. By default this is configured so
                        overcloud nodes can pull containers from the
                        undercloud registry.
  --cephadm-ssh-user CEPHADM_SSH_USER
                        Name of the SSH user used by cephadm. Warning: if this
                        option is used, it must be used consistently for every
                        'openstack overcloud ceph' call. Defaults to 'ceph-
                        admin'. (default=Env: CEPHADM_SSH_USER)
  --stack STACK         Name or ID of heat stack (default=Env:
                        OVERCLOUD_STACK_NAME)
  --working-dir WORKING_DIR
                        The working directory for the deployment where all
                        input, output, and generated files will be stored.
                        Defaults to "$HOME/overcloud-deploy/<stack>"
  --roles-data ROLES_DATA
                        Path to an alternative roles_data.yaml. Used to decide
                        which node gets which Ceph mon, mgr, or osd service
                        based on the node's role in <deployed_baremetal.yaml>.
  --network-data NETWORK_DATA
                        Path to an alternative network_data.yaml. Used to
                        define Ceph public_network and cluster_network. This
                        file is searched for networks with name_lower values
                        of storage and storage_mgmt. If none found, then
                        search repeats but with service_net_map_replace in
                        place of name_lower. Use --public-network-name or
                        --cluster-network-name options to override name of the
                        searched for network from storage or storage_mgmt to a
                        customized name. If network_data has no storage
                        networks, both default to ctlplane. If found network
                        has >1 subnet, they are all combined (for routed
                        traffic). If a network has ipv6 true, then the
                        ipv6_subnet is retrieved instead of the ip_subnet, and
                        the Ceph global ms_bind_ipv4 is set false and the
                        ms_bind_ipv6 is set true. Use --config to override
                        these defaults if desired.
  --public-network-name PUBLIC_NETWORK_NAME
                        Name of the network defined in network_data.yaml which
                        should be used for the Ceph public_network. Defaults
                        to 'storage'.
  --cluster-network-name CLUSTER_NETWORK_NAME
                        Name of the network defined in network_data.yaml which
                        should be used for the Ceph cluster_network. Defaults
                        to 'storage_mgmt'.
  --cluster CLUSTER     Name of the Ceph cluster. If set to 'foo', then the
                        files /etc/ceph/<FSID>/foo.conf and
                        /etc/ceph/<FSID>/foo.client.admin.keyring will be
                        created. Otherwise these files will use the name
                        'ceph'. Changing this means changing command line
                        calls too, e.g. 'ceph health' will become 'ceph
                        --cluster foo health' unless export CEPH_ARGS='--
                        cluster foo' is used.
  --mon-ip MON_IP       IP address of the first Ceph monitor. If not set, an
                        IP from the Ceph public_network of a server with the
                        mon label from the Ceph spec is used. IP must already
                        be active on server.
  --config CONFIG       Path to an existing ceph.conf with settings to be
                        assimilated by the new cluster via 'cephadm bootstrap
                        --config'
  --cephadm-extra-args CEPHADM_EXTRA_ARGS
                        String of extra parameters to pass cephadm. E.g. if
                        --cephadm-extra-args '--log-to-file --skip-prepare-
                        host', then cephadm boostrap will use those options.
                        Warning: requires --force as not all possible options
                        ensure a functional deployment.
  --force               Run command regardless of consequences.
  --ansible-extra-vars ANSIBLE_EXTRA_VARS
                        Path to an existing Ansible vars file which can
                        override any variable in tripleo-ansible. If '--
                        ansible-extra-vars vars.yaml' is passed, then
                        'ansible-playbook -e @vars.yaml ...' is used to call
                        tripleo-ansible Ceph roles. Warning: requires --force
                        as not all possible options ensure a functional
                        deployment.
  --ceph-client-username CEPH_CLIENT_USERNAME
                        Name of the cephx user. E.g. if 'openstack' is used,
                        then 'ceph auth get client.openstack' will return a
                        working user with key and capabilities on the deployed
                        Ceph cluster. Ignored unless tripleo_cephadm_pools is
                        set via --ansible-extra-vars. If this parameter is not
                        set and tripleo_cephadm_keys is set via --ansible-
                        extra-vars, then 'openstack' will be used. Used to set
                        CephClientUserName in --output.
  --ceph-client-key CEPH_CLIENT_KEY
                        Value of the cephx key. E.g.
                        'AQC+vYNXgDAgAhAAc8UoYt+OTz5uhV7ItLdwUw=='. Ignored
                        unless tripleo_cephadm_pools is set via --ansible-
                        extra-vars. If this parameter is not set and
                        tripleo_cephadm_keys is set via --ansible-extra-vars,
                        then a random key will be generated. Used to set
                        CephClientKey in --output.
  --skip-cephx-keys     Do not create cephx keys even if tripleo_cephadm_pools
                        is set via --ansible-extra-vars. If this option is
                        used, then even the defaults of --ceph-client-key and
                        --ceph-client-username are ignored, but the pools
                        defined via --ansible-extra-vars are still be created.
  --ceph-vip CEPH_VIP   Path to an existing Ceph services/network mapping
                        file.
  --daemons DAEMONS     Path to an existing Ceph daemon options definition.
  --single-host-defaults
                        Adjust configuration defaults to suit a single-host
                        Ceph cluster.
  --ceph-spec CEPH_SPEC
                        Path to an existing Ceph spec file. If not provided a
                        spec will be generated automatically based on --roles-
                        data and <deployed_baremetal.yaml>. The
                        <deployed_baremetal.yaml> parameter is optional only
                        if --ceph-spec is used.
  --osd-spec OSD_SPEC   Path to an existing OSD spec file. Mutually exclusive
                        with --ceph-spec. If the Ceph spec file is generated
                        automatically, then the OSD spec in the Ceph spec file
                        defaults to {data_devices: {all: true}} for all
                        service_type osd. Use --osd-spec to override the
                        data_devices value inside the Ceph spec file.
  --crush-hierarchy CRUSH_HIERARCHY
                        Path to an existing crush hierarchy spec file.
  --standalone          Use single host Ansible inventory. Used only for
                        development or testing environments.
  --container-image-prepare CONTAINER_IMAGE_PREPARE
                        Path to an alternative
                        container_image_prepare_defaults.yaml. Used to control
                        which Ceph container is pulled by cephadm via the
                        ceph_namespace, ceph_image, and ceph_tag variables in
                        addition to registry authentication via
                        ContainerImageRegistryCredentials.
  --cephadm-default-container
                        Use the default continer defined in cephadm instead of
                        container_image_prepare_defaults.yaml. If this is
                        used, 'cephadm bootstrap' is not passed the --image
                        parameter.

container-image-prepare overrides:
  The following options may be used to override individual values set via
  --container-image-prepare. If the example variables below were set the
  image would be concatenated into quay.io/ceph/ceph:latest and a custom
  registry login would be used.

  --container-namespace CONTAINER_NAMESPACE
                        e.g. quay.io/ceph
  --container-image CONTAINER_IMAGE
                        e.g. ceph
  --container-tag CONTAINER_TAG
                        e.g. latest
  --registry-url REGISTRY_URL
  --registry-username REGISTRY_USERNAME
  --registry-password REGISTRY_PASSWORD

This command is provided by the python-tripleoclient plugin.
$

Run openstack overcloud ceph deploy –help in your own environment to see the latest options which you have available.

Ceph Configuration Options

Any initial Ceph configuration options may be passed to a new cluster by putting them in a standard ini-style configuration file and using cephadm bootstrap –config option. The exact same option is passed through to cephadm with openstack overcloud ceph deploy –config:

$ cat <<EOF > initial-ceph.conf
[global]
ms_cluster_mode: secure
ms_service_mode: secure
ms_client_mode: secure
EOF
$ openstack overcloud ceph deploy --config initial-ceph.conf ...

The above example shows how to configure the messenger v2 protocol to use a secure mode that encrypts all data passing over the network.

The deployed_ceph.yaml Heat environment file output by openstack overcloud ceph deploy has ApplyCephConfigOverridesOnUpdate set to true. This means that services not covered by deployed ceph, e.g. RGW, can have the configuration changes that they need applied during overcloud deployment. After the deployed ceph process has run and then after the overcloud is deployed, it is recommended to update the deployed_ceph.yaml Heat environment file, or similar, to set ApplyCephConfigOverridesOnUpdate to false. Any subsequent Ceph configuration changes should then be made by the ceph config command.

It is supported to pass through the cephadm –single-host-defaults option, which configures a Ceph cluster to run on a single host:

openstack overcloud ceph deploy --single-host-defaults

Any option available from running cephadm bootstrap –help may be passed through openstack overcloud ceph deploy with the –cephadm-extra-args argument. For example:

openstack overcloud ceph deploy --force \
  --cephadm-extra-args '--log-to-file --skip-prepare-host' \
  ...

When the above is run the following will be run on the cephadm bootstrap node (the first controller node by default) on the overcloud:

cephadm bootstrap --log-to-file --skip-prepare-host ...

The –force option is required when using –cephadm-extra-args because not all possible options ensure a functional deployment.

Placement Groups (PGs)

When Ceph is initially deployed with openstack overcloud ceph deploy the PG and replica count settings are not changed from Ceph’s own defaults unless their parameters (osd_pool_default_size, osd_pool_default_pg_num, osd_pool_default_pgp_num) are included in an initial Ceph configuration file which can be passed with the –config option. These settings may also be modified after openstack overcloud ceph deploy.

The deprecated Heat paramters CephPoolDefaultSize and CephPoolDefaultPgNum no longer have any effect as these configurations are not made during overcloud deployment. However, during overcloud deployment pools are created and both the target_size_ratio or pg_num per pool may be set at that point. See the “Ceph Pool Options” section for more details.

Ceph Name Options

To deploy with a different cluster name than the default of “ceph” use the --cluster option:

openstack overcloud ceph deploy \
        --cluster central \
        ...

The above will result in keyrings and Ceph configuration files being created with the name passed to cluster, for example:

[root@oc0-controller-0 ~]# ls -l /etc/ceph/
total 16
-rw-------. 1 root root  63 Mar 26 21:49 central.client.admin.keyring
-rw-------. 1  167  167 201 Mar 26 22:17 central.client.openstack.keyring
-rw-------. 1  167  167 134 Mar 26 22:17 central.client.radosgw.keyring
-rw-r--r--. 1 root root 177 Mar 26 21:49 central.conf
[root@oc0-controller-0 ~]#

When cephadm shell is run on an overcloud node like the above, Ceph commands might return the error monclient: get_monmap_and_config cannot identify monitors to contact because the default “ceph” name is not used. Thus, if the --cluster is used when deploying Ceph, then use options like the following to run cephadm shell after deployment:

cephadm shell --config /etc/ceph/central.conf \
              --keyring /etc/ceph/central.client.admin.keyring

Another solution is to use the following before running ceph commands:

cephadm shell --mount /etc/ceph:/etc/ceph
export CEPH_ARGS='--cluster central'

After using either of the above standard Ceph commands should work within the cephadm shell container.

Ceph Spec Options

The roles file, described in the next section, and the output of openstack overcloud node provision are passed to the ceph_spec_bootstrap Ansible module to create a Ceph Service Specification. The openstack overcloud ceph deploy command does this automatically so that a spec does not usually need to be generated separately. However, it is possible to generate a ceph spec before deployment with the following command:

$ openstack overcloud ceph spec --help
usage: openstack overcloud ceph spec [-h] -o <ceph_spec.yaml> [-y]
                                     [--stack STACK]
                                     [--working-dir WORKING_DIR]
                                     [--roles-data ROLES_DATA]
                                     [--mon-ip MON_IP] [--standalone]
                                     [--osd-spec OSD_SPEC | --crush-hierarchy CRUSH_HIERARCHY]
                                     [<deployed_baremetal.yaml>]

positional arguments:
  <deployed_baremetal.yaml>
                        Path to the environment file output from "openstack
                        overcloud node provision". This argument may be
                        excluded only if --standalone is used.

optional arguments:
  -h, --help            show this help message and exit
  -o <ceph_spec.yaml>, --output <ceph_spec.yaml>
                        The path to the output cephadm spec file to pass to
                        the "openstack overcloud ceph deploy --ceph-spec
                        <ceph_spec.yaml>" command.
  -y, --yes             Skip yes/no prompt before overwriting an existing
                        <ceph_spec.yaml> output file (assume yes).
  --stack STACK
                        Name or ID of heat stack (default=Env:
                        OVERCLOUD_STACK_NAME)
  --working-dir WORKING_DIR
                        The working directory for the deployment where all
                        input, output, and generated files will be stored.
                        Defaults to "$HOME/overcloud-deploy/<stack>"
  --roles-data ROLES_DATA
                        Path to an alternative roles_data.yaml. Used to decide
                        which node gets which Ceph mon, mgr, or osd service
                        based on the node's role in <deployed_baremetal.yaml>.
  --mon-ip MON_IP
                        IP address of the first Ceph monitor. Only available
                        with --standalone.
  --standalone          Create a spec file for a standalone deployment. Used
                        for single server development or testing environments.
  --osd-spec OSD_SPEC
                        Path to an existing OSD spec file. When the Ceph spec
                        file is generated its OSD spec defaults to
                        {data_devices: {all: true}} for all service_type osd.
                        Use --osd-spec to override the data_devices value
                        inside the Ceph spec file.
  --crush-hierarchy CRUSH_HIERARCHY
                        Path to an existing crush hierarchy spec file.
$

The spec file may then be edited if desired and passed directly like this:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --ceph-spec ~/ceph_spec.yaml

Overriding which disks should be OSDs

The Advanced OSD Service Specifications should be used to define how disks are used as OSDs.

By default all available disks (excluding the disk where the operating system is installed) are used as OSDs. This is because the default spec has the following:

data_devices:
  all: true

In the above example, the data_devices key is valid for any Ceph Service Specification whose service_type is “osd”. Other OSD service types, as found in the Advanced OSD Service Specifications, may be set by using the --osd-spec option.

If the file osd_spec.yaml contains the following:

data_devices:
  rotational: 1
db_devices:
  rotational: 0

and the following command is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --osd-spec osd_spec.yaml

Then all rotating devices will be data devices and all non-rotating devices will be used as shared devices (wal, db). This is because when the dynamic Ceph service specification is built, whatever is in the file referenced by --osd-spec will be appended to the section of the specification if the service_type is “osd”. The same --osd-spec is available to the openstack overcloud ceph spec command.

The Provisioning of node-specific Hieradata feature is not supported by the cephadm integration but the Advanced OSD Service Specifications has a host_pattern parameter which specifies which host to target for certain data_devices definitions, so the equivalent functionality is available but with the new syntax.

Service Placement Options

The Ceph services defined in the roles_data.yaml file as described in Deploying with Composable Services determine which baremetal node runs which service. By default the Controller role has the CephMon and CephMgr service while the CephStorage role has the CephOSD service. Most composable services require Heat output in order to determine how services are configured, but not the Ceph services. Thus, the roles_data.yaml file remains authoritative for Ceph service placement even though the “Deployed Ceph” process happens before Heat is run.

It is only necessary to use the –roles-file option if the default roles_data.yaml file is not being used. For example if you intend to deploy hyperconverged nodes, then you want the predeployed compute nodes to be in the ceph spec with the “osd” label and for the service_type “osd” to have a placement list containing a list of the compute nodes. To do this generate a custom roles file as described in Deploying with Composable Services like this:

openstack overcloud roles generate Controller ComputeHCI > custom_roles.yaml

and then pass that roles file like this:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --roles-data custom_roles.yaml

After running the above the compute nodes should have running OSD containers and when the overcloud is deployed Nova compute services will then be set up on the same hosts.

If you wish to generate the ceph spec with the modified placement described above before the ceph deployment, then the same roles file may be passed to the ‘openstack overcloud ceph spec’ command:

openstack overcloud ceph spec \
        --stack overcloud \
        --roles-data custom_roles.yaml \
        --output ceph_spec.yaml \
        deployed_metal.yaml

In the above example the –stack is used in order to find the working directory containing the Ansible inventory which was created when openstack overcloud node provision was run.

Ceph VIP Options

The –ceph-vip option may be used to reserve a VIP for each Ceph service specified by the ‘service/network’ mapping defined as input. A generic ceph service mapping can be something like the following:

---
ceph_services:
  - service: ceph_nfs
    network: storage_cloud_0
  - service: ceph_rgw
    network: storage_cloud_0

For each service added to the list above, a virtual IP on the specified network is created to be used as frontend_vip of the ingress daemon. When no subnet is specified, a default <network>_subnet pattern is used. If the subnet does not follow the <network>_subnet pattern, a subnet for the VIP may be specified per service:

---
ceph_services:
  - service: ceph_nfs
    network: storage_cloud_0
  - service: ceph_rgw
    network: storage_cloud_0
    subnet: storage_leafX

When the subnet parameter is provided, it will be used by the tripleo_service_vip Ansible module, otherwise the default pattern is followed. This feature also supports the fixed_ips mode. When fixed IPs are defined, the module is able to use that input to reserve the VIP on that network. A valid input can be something like the following:

---
fixed: true
ceph_services:
  - service: ceph_nfs
    network: storage_cloud_0
    ip_address: 172.16.11.159
  - service: ceph_rgw
    network: storage_cloud_0
    ip_address: 172.16.11.160

When the boolean fixed is set to True, the subnet pattern is ignored, and a sanity check on the user input is performed, looking for the ip_address keys associated to the specified services. If the fixed keyword is missing, the subnet pattern is followed. When the environment file containing the ‘ceph service/network’ mapping described above is created, it can be passed to the ceph deploy command via the –ceph-vip option:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --ceph-vip ~/ceph_services.yaml

Deploy additional daemons

A new option –daemons for the openstack overcloud ceph deploy command has been added and may be used to define additional Ceph daemons that are deployed during the Ceph provisioning process. This option requires a data structure which defines the services to be deployed:

ceph_nfs:
  cephfs_data: 'manila_data'
  cephfs_metadata: 'manila_metadata'
ceph_rgw: {}
ceph_ingress:
  tripleo_cephadm_haproxy_container_image: undercloud.ctlplane.mydomain.tld:8787/ceph/haproxy:2.3
  tripleo_cephadm_keepalived_container_image: undercloud.ctlplane.mydomain.tld:8787/ceph/keepalived:2.5.1

For each service added to the data structure above, additional options can be defined and passed as extra_vars to the tripleo-ansible flow. If no option is specified, the default values provided by the cephadm tripleo-ansible role will be used.

Example: deploy HA Ceph NFS daemon

Cephadm is able to deploy and manage the lifecycle of a highly available ceph-nfs daemon, called CephIngress, which uses haproxy and keepalived. The –daemon option described in the previous section, provides:

  1. a stable, VIP managed by keepalived used to access the NFS service

  2. fail-over between hosts in case of failure

  3. load distribution across multiple NFS gateways through Haproxy

To deploy a cephadm managed ceph-nfs daemon with the related ingress service, create a ceph_daemons.yaml spec file with the following definition:

ceph_nfs:
  cephfs_data: 'manila_data'
  cephfs_metadata: 'manila_metadata'
ceph_ingress:
  tripleo_cephadm_haproxy_container_image: undercloud.ctlplane.mydomain.tld:8787/ceph/haproxy:2.3
  tripleo_cephadm_keepalived_container_image: undercloud.ctlplane.mydomain.tld:8787/ceph/keepalived:2.5.1

When the environment file containing the services definition described above is created, it can be passed to the ceph deploy command via the –daemon option:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --ceph-vip ~/ceph_services.yaml \
        --daemon ~/ceph_daemons.yaml

Note

A VIP must be reserved for the ceph_nfs service and passed to the command above. For further information on reserving a VIP for a Ceph service, see Ceph VIP Options.

Crush Hierarchy Options

The ceph_spec_bootstrap Ansible module is used to generate the Ceph related spec file which is applied using the Ceph orchestrator tool. During the Ceph OSDs deployment, a custom crush hierarchy can be defined and passed using the --crush-hierarchy option. As per Ceph Host Management, by doing this the location attribute is added to the Hosts spec. The location attribute will only affect the initial CRUSH location Subsequent changes of the location property will be ignored. Also, removing a host will not remove any CRUSH generated bucket.

Example: Apply a custom crush hierarchy to the deployed OSDs

If the file crush_hierarchy.yaml contains something like the following:

---
ceph_crush_hierarchy:
  ceph-0:
    root: default
    rack: r0
  ceph-1:
    root: default
    rack: r1
  ceph-2:
    root: default
    rack: r2

and the following command is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --osd-spec osd_spec.yaml \
        --crush-hierarchy crush_hierarchy.yaml

Then the Ceph cluster will bootstrap with the following Ceph OSD layout:

[ceph: root@ceph-0 /]# ceph osd tree
ID  CLASS  WEIGHT   TYPE NAME                  STATUS  REWEIGHT  PRI-AFF
-1         0.02939  root default
-3         0.00980      rack r0
-2         0.00980          host ceph-node-00
 0    hdd  0.00980              osd.0              up   1.00000  1.00000
-5         0.00980      rack r1
-4         0.00980          host ceph-node-01
 1    hdd  0.00980              osd.1              up   1.00000  1.00000
-7         0.00980      rack r2
-6         0.00980          host ceph-node-02
 2    hdd  0.00980              osd.2              up   1.00000  1.00000

Note

Device classes are automatically detected by Ceph, but crush rules are associated to pools and they still be defined using the CephCrushRules parameter during the overcloud deployment. Additional details can be found in the “Overriding CRUSH rules” section below.

Network Options

The storage networks defined in the network_data.yaml file as described in Deploying with Custom Networks determine which networks Ceph is configured to use. When using network isolation, the standard is for TripleO to deploy two storage networks which map to the two Ceph networks in the following way:

  • storage - Storage traffic, the Ceph public_network, e.g. Nova compute nodes use this network for RBD traffic to the Ceph cluster.

  • storage_mgmt - Storage management traffic (such as replication traffic between storage nodes), the Ceph cluster_network, e.g. Ceph OSDs use this network to replicate data.

openstack overcloud ceph deploy will use the network_data.yaml file specified by the --network-data option to determine which networks should be used for the public_network and cluster_network. It assumes these networks are named storage and storage_mgmt in the network_data.yaml file unless a different name should be used as indicated by the --public-network-name and --cluster-network-name options.

It is necessary to use the --network-data option when deploying with network isolation. Otherwise the default network, i.e. the ctlplane network on the undercloud (192.168.24.0/24), will be used for both the public_network and cluster_network.

Example: Multiple subnets with custom network names

If network_data.yaml contains the following:

- name: StorageMgmtCloud0
  name_lower: storage_mgmt_cloud_0
  service_net_map_replace: storage_mgmt
  subnets:
    storage_mgmt_cloud_0_subnet12:
      ip_subnet: '172.16.12.0/24'
    storage_mgmt_cloud_0_subnet13:
      ip_subnet: '172.16.13.0/24'
- name: StorageCloud0
  name_lower: storage_cloud_0
  service_net_map_replace: storage
  subnets:
    storage_cloud_0_subnet14:
      ip_subnet: '172.16.14.0/24'
    storage_cloud_0_subnet15:
      ip_subnet: '172.16.15.0/24'

Then the Ceph cluster will have the following parameters set:

[global]
public_network = '172.16.14.0/24,172.16.15.0/24'
cluster_network = '172.16.12.0/24,172.16.13.0/24'
ms_bind_ipv4 = True
ms_bind_ipv6 = False

This is because the TripleO client will see that though the name_lower value does not match storage or storage_mgmt (they match the custom names storage_cloud_0 and storage_mgmt_cloud_0 instead), those names do match the service_net_map_replace values. If service_net_map_replace is in the network_data.yaml, then it is not necessary to use the --public-network-name and --cluster-network-name options. Alternatively the service_net_map_replace key could have been left out and the --public-network-name and --cluster-network-name options could have been used instead. Also, because multiple subnets are used they are concatenated and it is assumed that there is routing between the subnets. If there was no subnets key, in the network_data.yaml file, then the client would have looked instead for the single ip_subnet key for each network.

By default the Ceph global ms_bind_ipv4 is set true and ms_bind_ipv6 is set false.

Example: IPv6

If network_data.yaml contains the following:

- name: Storage
  ipv6: true
  ipv6_subnet: fd00:fd00:fd00:3000::/64
  name_lower: storage
- name: StorageMgmt
  ipv6: true
  ipv6_subnet: fd00:fd00:fd00:4000::/64
  name_lower: storage_mgmt

Then the Ceph cluster will have the following parameters set:

[global]
public_network = fd00:fd00:fd00:3000::/64
cluster_network = fd00:fd00:fd00:4000::/64
ms_bind_ipv4 = False
ms_bind_ipv6 = True

Because the storage networks in network_data.yaml contain ipv6: true, the ipv6_subet values are extracted and the Ceph globals ms_bind_ipv4 is set false and ms_bind_ipv6 is set true. It is not supported to have the public_network use IPv4 and the cluster_network use IPv6 or vice versa.

Example: Directly setting network and ms_bind options

If the examples above are not sufficient for your Ceph network needs, then it’s possible to create an initial-ceph.conf with the four parameters public_network, cluster_network, ms_bind_ipv4, and ms_bind_ipv6 options set to whatever values are desired.

When using the --config option it is still important to ensure the TripleO storage and storage_mgmt network names map to the correct public_network and cluster_network so that the rest of the deployment is consistent.

The four parameters, public_network, cluster_network, ms_bind_ipv4, and ms_bind_ipv6, are always set in the Ceph cluster (with ceph config set global) from the --network-data file unless those parameters are explicitly set in the --config file. In that case the values in the --network-data file are not set directly in the Ceph cluster though other aspects of the overcloud deployment treat the --network-data file as authoritative (e.g. when Ceph RGW is set) so both sources should be consistent if the --config file has any of these four parameters.

An example of setting the four parameters in the initial Ceph configuration is below:

$ cat <<EOF > initial-ceph.conf
[global]
public_network = 'fd00:fd00:fd00:3000::/64,172.16.14.0/24'
cluster_network = 'fd00:fd00:fd00:4000::/64,172.16.12.0/24'
ms_bind_ipv4 = true
ms_bind_ipv6 = true
EOF
$ openstack overcloud ceph deploy \
  --config initial-ceph.conf --network-data network_data.yaml

The above assumes that network_data.yaml contains the following:

- name: Storage
  ipv6_subnet: fd00:fd00:fd00:3000::/64
  ip_subnet: 172.16.14.0/24
  name_lower: storage
- name: StorageMgmt
  ipv6_subnet: fd00:fd00:fd00:4000::/64
  ip_subnet: 172.16.12.0/24
  name_lower: storage_mgmt

The above settings, which mix IPv4 and IPv6, are experimental and untested.

SSH User Options

Cephadm must use SSH to connect to all remote Ceph hosts that it manages. The “Deployed Ceph” feature creates an account and SSH key pair on all Ceph nodes in the overcloud and passes this information to cephadm so that it uses this account instead of creating its own. The openstack overcloud ceph deploy command will automatically create this user and distribute their SSH keys. It’s also possible to create this user and distribute the associated keys in a separate step by running openstack overcloud ceph user enable and then when calling openstack overcloud ceph deploy with the –skip-user-create option. By default the user is called ceph-admin though both commands support the –cephadm-ssh-user option to set a different name. If this option is used though, it must be used consistently for every openstack overcloud ceph call.

The openstack overcloud ceph user disable –fsid <FSID> command may be run after openstack overcloud ceph deploy has been run to disable cephadm so that it may not be used to administer the Ceph cluster and no ceph orch … CLI commands will function. This will also prevent Ceph node overcloud scale operations though the Ceph cluster will still be able to read and write data. This same command will also remove the public and private SSH keys of the cephadm SSH user on overclouds which host Ceph. The “ceph user enable” option may then be used to re-distribute the public and private SSH keys of the cephadm SSH user and re-enable the cephadm mgr module. openstack overcloud ceph user enable will only re-enable the cephadm mgr module if it is passed the FSID with the –fsid <FSID> option. The FSID may be found in the deployed_ceph.yaml Heat environment file which is generated by the openstack overcloud ceph deploy -o deployed_ceph.yaml command.

Warning

Disabling cephadm will disable all Ceph management features described in this document. The openstack overcloud ceph user disable command is not recommended unless you have a good reason to disable cephadm.

Both the openstack overcloud ceph user enable and openstack overcloud ceph user disable commands require the path to an existing Ceph spec file to be passed as an argument. This is necessary in order to determine which hosts require the cephadm SSH user and which of those hosts require the private SSH key. Only hosts with the _admin label get the private SSH since they need to be able to SSH into other Ceph hosts. In the average deployment with three monitor nodes this is three hosts. All other Ceph hosts only get the public key added to the users authorized_keys file.

See the “Ceph Spec Options” options of this document for where to find this file or how to automatically generate one before Ceph deployment if you plan to call openstack overcloud ceph user enable before calling openstack overcloud ceph deploy. See openstack overcloud ceph user enable –help and openstack overcloud ceph user disable –help for more information.

Container Options

As described in Container Image Preparation the undercloud may be used as a container registry for ceph containers and there is a supported syntax to download containers from authenticated registries.

By default openstack overcloud ceph deploy will pull the Ceph container in the default container_image_prepare_defaults.yaml file. If a push_destination is defined in this file, then the overcloud will be configured so it can access the local registry in order to download the Ceph container. This means that openstack overcloud ceph deploy will modify the overcloud’s /etc/hosts and /etc/containers/registries.conf files; unless the –skip-hosts-config and –skip-container-registry-config options are used or a push_destination is not defined.

The version of the Ceph used in each OpenStack release changes per release and can be seen by running a command like this:

egrep "ceph_namespace|ceph_image|ceph_tag" \
  /usr/share/tripleo-common/container-images/container_image_prepare_defaults.yaml

The –container-image-prepare option can be used to override which container_image_prepare_defaults.yaml file is used. If a version of this file called custom_container_image_prepare.yaml is modified to contain syntax like the following:

ContainerImageRegistryCredentials:
  quay.io/ceph-ci:
    quay_username: quay_password

Then when a command like the following is run:

openstack overcloud ceph deploy \
        deployed_metal.yaml \
        -o deployed_ceph.yaml \
        --container-image-prepare custom_container_image_prepare.yaml

The credentials will be extracted from the file and the tripleo ansible role to bootstrap Ceph will be executed like this:

cephadm bootstrap
 --registry-url quay.io/ceph-ci
 --registry-username quay_username
 --registry-password quay_password
 ...

The syntax of the container image prepare file can also be ignored and instead the following command line options may be used instead:

--container-namespace CONTAINER_NAMESPACE
                      e.g. quay.io/ceph
--container-image CONTAINER_IMAGE
                      e.g. ceph
--container-tag CONTAINER_TAG
                      e.g. latest
--registry-url REGISTRY_URL
--registry-username REGISTRY_USERNAME
--registry-password REGISTRY_PASSWORD

If a variable above is unused, then it defaults to the ones found in the default container_image_prepare_defaults.yaml file. In other words, the above options are overrides.

Creating Pools and CephX keys before overcloud deployment (Optional)

By default openstack overcloud ceph deploy does not create Ceph pools or cephx keys to access those pools. Later during overcloud deployment the pools and cephx keys are created based on which Heat environment files are passed. For most cases only pools for Cinder (volumes), Nova (vms), and Glance (images) are created but if the Heat environment file to configure additional services are passed, e.g. cinder-backup, then the required pools are created. This is covered in more detail in the next section of this document.

It is not necessary to create pools and cephx keys before overcloud deployment but it is possible. The Ceph pools can be created when openstack overcloud ceph deploy is run by using the option –ansible-extra-vars to set the tripleo_cephadm_pools variable used by tripleo-ansible’s tripleo_cephadm role.

Create an Ansible extra vars file defining the desired pools:

cat <<EOF > tripleo_cephadm_ansible_extra_vars.yaml
---
tripleo_cephadm_pools:
  - name: vms
    pg_autoscale_mode: True
    target_size_ratio: 0.3
    application: rbd
  - name: volumes
    pg_autoscale_mode: True
    target_size_ratio: 0.5
    application: rbd
  - name: images
    target_size_ratio: 0.2
    pg_autoscale_mode: True
    application: rbd
tripleo_ceph_client_vars: /home/stack/overcloud-deploy/overcloud/cephadm/ceph_client.yml
EOF

The pool names ‘vms’, ‘volumes’, and ‘images’ used above are recommended since those are the default names that the overcloud deployment will use when “openstack overcloud deploy” is run, unless the Heat parameters NovaRbdPoolName, CinderRbdPoolName, and GlanceRbdPoolName are overridden respectively.

In the above example, tripleo_ceph_client_vars is used to direct Ansible to save the generated ceph_client.yml file in a cephadm subdirectory of the working directory. The tripleo_cephadm role will ensure this directory exists before creating the file. If openstack overcloud export ceph is going to be used, it will expect the Ceph client file to be in this location, based on the stack name (e.g. overcloud).

Deploy the Ceph cluster with Ansible extra vars:

openstack overcloud ceph deploy \
        deployed-metal-overcloud.yaml \
        -y -o deployed-ceph-overcloud.yaml \
        --force \
        --ansible-extra-vars tripleo_cephadm_ansible_extra_vars.yaml

After Ceph is deployed, the pools should be created and an openstack cephx key will also be created to access all of those pools. The contents of deployed-ceph-overcloud.yaml will also have the pool and cephx key Heat environment parameters set so the overcloud will use the same values.

When the tripleo_cephadm_pools variable is set, the Tripleo client will create a tripleo_cephadm_keys tripleo-ansible variable structure with the client name “openstack” and a generated cephx key like the following:

tripleo_cephadm_keys:
  - name: client.openstack
    key: AQC+vYNXgDAgAhAAc8UoYt+OTz5uhV7ItLdwUw==
    mode: '0600'
    caps:
      mgr: allow *
      mon: profile rbd
      osd: profile rbd pool=vms, profile rbd pool=volumes, profile rbd pool=images

It is not recommended to define tripleo_cephadm_keys in the Ansible extra vars file. If you prefer to set the key username to something other than “openstack” or prefer to pass your own cephx client key (e.g. AQC+vYNXgDAgAhAAc8UoYt+OTz5uhV7ItLdwUw==), then use following parameters:

--ceph-client-username (default: openstack)
--ceph-client-key (default: auto generates a valid cephx key)

Both of the above parameters are ignored unless tripleo_cephadm_pools is set via –ansible-extra-vars. If tripleo_cephadm_pools is set then a cephx key to access all of the pools will always be created unless –skip-cephx-keys is used.

If you wish to re-run ‘openstack overcloud ceph deploy’ for any reason and have created-cephx keys in previous runs, then you may use the –ceph-client-key parameter from the previous run to prevent a new key from being generated. The key value can be found in the file which is output from he previous run (e.g. –output <deployed_ceph.yaml>).

If any of the above parameters are used, then the generated deployed Ceph output file (e.g. –output <deployed_ceph.yaml>) will contain the values of the above variables mapped to their TripleO Heat template environment variables to ensure a consistent overcloud deployment:

CephPools: {{ tripleo_cephadm_pools }}
CephClientConfigVars: {{ tripleo_ceph_client_vars }}
CephClientKey: {{ ceph_client_username }}
CephClientUserName: {{ ceph_client_key }}

The CephPools Heat parameter above has always supported idempotent updates. It will be pre-populated with the pools from tripleo_cephadm_pools after Ceph is deployed. The deployed_ceph.yaml which is output can also be updated so that additional pools can be created when the overcloud is deployed. The Heat parameters above are described in more detail in the rest of this document.

Environment files to configure Ceph during Overcloud deployment

After openstack overcloud ceph deploy has run and output the deployed_ceph.yaml file, this file and other Heat environment files should be passed to the openstack overcloud deploy command:

openstack overcloud deploy --templates \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm.yaml \
  -e deployed_ceph.yaml

The above will make the following modifications to the Ceph cluster while the overcloud is being deployed:

  • Execute cephadm to add the Ceph RADOS Gateway (RGW) service

  • Configure HAProxy as a front end for RGW

  • Configure Keystone so RGW behaves like the OpenStack object service

  • Create Pools for both RGW and RBD services

  • Create an openstack client cephx keyring for Nova, Cinder, Glance to access RBD

The information necessary to configure Ceph clients will then be extracted to /home/stack/ceph_client.yml on the undercloud and passed to the as input to the tripleo-ansible role tripleo_ceph_client which will then configure the rest of the overcloud to use the new Ceph cluster as described in the Use an external Ceph cluster with the Overcloud documentation.

If you only wish to deploy Ceph RBD without RGW then use the following variation of the above:

openstack overcloud deploy --templates \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm-rbd-only.yaml \
  -e deployed_ceph.yaml

Do not directly edit the environments/cephadm/cephadm.yaml or cephadm-rbd-only.yaml file. If you wish to override the defaults, as described below in the sections starting with “Overriding”, then place those overrides in a separate cephadm-overrides.yaml file and deploy like this:

openstack overcloud deploy --templates \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm.yaml \
  -e deployed_ceph.yaml \
  -e ceph-overrides.yaml

Applying Ceph server configuration during overcloud deployment

The deployed_ceph.yaml file output by openstack overcloud ceph deploy has the paramter ApplyCephConfigOverridesOnUpdate set to true so that Ceph services not deployed by openstack overcloud ceph deploy, e.g. RGW, can be configured during initial overcloud deployment. After both Ceph and the overcloud have been deployed, edit the deployed_ceph.yaml file and set ApplyCephConfigOverridesOnUpdate to false. All Ceph server configuration changes should then be made using Ceph Orchestrator.

It is technically possible to set ApplyCephConfigOverridesOnUpdate to true and use CephConfigOverrides to override Ceph server configurations during stack updates. When this happens, parameters in CephConfigOverrides are put into a file, e.g. assimilate_ceph.conf, and a command like ceph config assimilate-conf -i assimilate_ceph.conf is run.

Regardless of the value of the ApplyCephConfigOverridesOnUpdate boolean, if openstack overcloud deploy is re-run in order to update the stack, the cephadm bootstrap process is not repeated because that process is only run if cephadm list returns an empty list.

Applying Ceph client configuration during overcloud deployment

To make a Ceph client configuration change, update the parameters in CephConfigOverrides and run a stack update. This will not change the configuration for the Ceph servers unless ApplyCephConfigOverridesOnUpdate is set to true (as described in the section above). By default it should only change configurations for the Ceph clients. Examples of Ceph clients include Nova compute containers, Cinder volume containers, Glance image containers, etc.

The CephConfigOverrides directive updates all Ceph client configuration files on the overcloud in the CephConfigPath (which defaults to /var/lib/tripleo-config/ceph). The CephConfigPath is mounted on the client containers as /etc/ceph. The name of the configuration file is ceph.conf because the CephClusterName parameter defaults to “ceph”. If CephClusterName was set to “foo”, then the file would be called /etc/ceph/foo.conf.

Ceph Pool Options

When openstack overcloud deploy is run a pool is created for each OpenStack service depending on if that service is enabled by including its Heat environment. For example, a command like the following will result in pools for Nova (vms), Cinder (volumes) and Glance (images) being created:

openstack overcloud deploy --templates \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm-rbd-only.yaml

If -e environments/cinder-backup.yaml included in the above command then a pool called backups would also be created.

By default each pool will have Ceph`s pg_autoscale_mode enabled so it is not necessary to directly set a PG number per pool. However, even with this mode enabled it is recommended to set a target_size_ratio (or pg_num) per pool in order to minimize data rebalancing. For more information on pg_autoscale_mode see Autoscaling Placement Groups.

To control the target_size_ratio per pool, create a Heat environment file like pools.yaml with the following content and include it in the openstack overcloud deploy command with a -e pools.yaml:

CephPools:
  - name: volumes
    target_size_ratio: 0.4
    application: rbd
  - name: images
    target_size_ratio: 0.1
    application: rbd
  - name: vms
    target_size_ratio: 0.3
    application: rbd

In the above example it is assumed that the percentage of data used per service will be Cinder volumes 40%, Glance images 10% and Nova vms 30% (with 20% of space free for other pools). It is worthwhile to set these values based on your expected usage (e.g. maybe 40% is not right for your usecase). If you do not override the CephPools parameter, then each pool will have Ceph’s default PG number. Though the autoscaler will adjust this number automatically over time based on usage, the data will be moved within the cluster as a result which will use computational resources.

If you prefer to set a PG number instead of a target size ratio, then replace target_size_ratio in the example above with ‘pg_num’ and supply a different integer per pool (e.g. 512 for volumes, 128 for images, etc.) based on your expected usage.

Overriding CRUSH rules

To deploy Ceph pools with custom CRUSH Map Rules use the CephCrushRules parameter to define a list of named rules and then associate the rule_name per pool with the CephPools parameter:

parameter_defaults:
  CephCrushRules:
    - name: HDD
      root: default
      type: host
      class: hdd
      default: true
    - name: SSD
      root: default
      type: host
      class: ssd
      default: false
  CephPools:
    - {'name': 'slow_pool', 'rule_name': 'HDD', 'application': 'rbd'}
    - {'name': 'fast_pool', 'rule_name': 'SSD', 'application': 'rbd'}

CRUSH rules may be created during overcloud deployment as documented above. CRUSH rules may also be created directly via the Ceph command line tools.

Overriding CephX Keys

During overcloud deployment, TripleO will create a Ceph cluster with a CephX key file for OpenStack RBD client connections that is shared by the Nova, Cinder, and Glance services to read and write to their pools. Not only will the keyfile be created but the Ceph cluster will be configured to accept connections when the key file is used. The file will be named ceph.client.openstack.keyring and it will be stored in /etc/ceph within the containers, but on the container host it will be stored in a location defined by a TripleO exposed parameter which defaults to /var/lib/tripleo-config/ceph.

The keyring file is created using the following defaults:

  • CephClusterName: ‘ceph’

  • CephClientUserName: ‘openstack’

  • CephClientKey: This value is randomly generated per Heat stack. If it is overridden the recommendation is to set it to the output of ceph-authtool –gen-print-key.

If the above values are overridden, the keyring file will have a different name and different content. E.g. if CephClusterName was set to ‘foo’ and CephClientUserName was set to ‘bar’, then the keyring file would be called foo.client.bar.keyring and it would contain the line [client.bar].

The CephExtraKeys parameter may be used to generate additional key files containing other key values and should contain a list of maps where each map describes an additional key. The syntax of each map must conform to what the ceph-ansible/library/ceph_key.py Ansible module accepts. The CephExtraKeys parameter should be used like this:

CephExtraKeys:
  - name: "client.glance"
    caps:
      mgr: "allow *"
      mon: "profile rbd"
      osd: "profile rbd pool=images"
    key: "AQBRgQ9eAAAAABAAv84zEilJYZPNuJ0Iwn9Ndg=="
    mode: "0600"

If the above is used, in addition to the ceph.client.openstack.keyring file, an additional file called ceph.client.glance.keyring will be created which contains:

[client.glance]
      key = AQBRgQ9eAAAAABAAv84zEilJYZPNuJ0Iwn9Ndg==
      caps mgr = "allow *"
      caps mon = "profile rbd"
      caps osd = "profile rbd pool=images"

The Ceph cluster will also allow the above key file to be used to connect to the images pool. Ceph RBD clients which are external to the overcloud could then use this CephX key to connect to the images pool used by Glance. The default Glance deployment defined in the Heat stack will continue to use the ceph.client.openstack.keyring file unless that Glance configuration itself is overridden.

Add the Ceph Dashboard to a Overcloud deployment

During the overcloud deployment most of the Ceph daemons can be added and configured. To deploy the ceph dashboard include the ceph-dashboard.yaml environment file as in the following example:

openstack overcloud deploy --templates \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm.yaml \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/ceph-dashboard.yaml

The command above will include the ceph dashboard related services and generates all the cephadm required variables to render the monitoring stack related spec that can be applied against the deployed Ceph cluster. When the deployment has been completed the Ceph dashboard containers, including prometheus and grafana, will be running on the controller nodes and will be accessible using the port 3100 for grafana and 9092 for prometheus; since this service is only internal and doesn’t listen on the public vip, users can reach both grafana and the exposed ceph dashboard using the controller provisioning network vip on the specified port (8444 is the default for a generic overcloud deployment).

The resulting deployment will be composed by an external stack made by grafana, prometheus, alertmanager, node-exporter containers and the ceph dashboard mgr module that acts as the backend for this external stack, embedding the grafana layouts and showing the ceph cluster specific metrics coming from prometheus. The Ceph Dashboard backend services run on the specified CephDashboardNetwork and CephGrafanaNetwork, while the high availability is realized by haproxy and Pacemaker.

The Ceph Dashboard frontend is fully integrated with the tls-everywhere framework, hence providing the tls environments files will trigger the certificate request for both grafana and the ceph dashboard: the generated crt and key files are then configured by cephadm, resulting in a key-value pair within the Ceph orchestrator, which is able to mount the required files to the dashboard related containers. The Ceph Dashboard admin user role is set to read-only mode by default for safe monitoring of the Ceph cluster. To permit an admin user to have elevated privileges to alter elements of the Ceph cluster with the Dashboard, the operator can change the default.

For this purpose, TripleO exposes a parameter that can be used to change the Ceph Dashboard admin default mode.

Log in to the undercloud as stack user and create the ceph_dashboard_admin.yaml environment file with the following content:

parameter_defaults:
   CephDashboardAdminRO: false

Run the overcloud deploy command to update the existing stack and include the environment file created with all other environment files that are already part of the existing deployment:

openstack overcloud deploy --templates \
  -e <existing_overcloud_environment_files> \
  -e ceph_dashboard_admin.yml

The ceph dashboard will also work with composable networks. In order to isolate the monitoring access for security purposes, operators can take advantage of composable networks and access the dashboard through a separate network vip. By doing this, it’s not necessary to access the provisioning network and separate authorization profiles may be implemented.

To deploy the overcloud with the ceph dashboard composable network we need first to generate the controller specific role created for this scenario:

openstack overcloud roles generate \
  -o /home/stack/roles_data.yaml \
  ControllerStorageDashboard Compute \
  BlockStorage ObjectStorage CephStorage

Finally, run the overcloud deploy command including the new generated roles_data.yaml and the network_data_dashboard.yaml file that will trigger the generation of this new network.

The final overcloud command must look like the following:

openstack overcloud deploy --templates \
  -r /home/stack/roles_data.yaml \
  -n /usr/share/openstack-tripleo-heat-templates/network_data_dashboard.yaml \
  -e /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm.yaml \
  -e ~/my-ceph-settings.yaml

Scenario: Deploy Ceph with TripleO and Metalsmith and then Scale Up

Deploy the hardware as described in Provisioning Baremetal Before Overcloud Deploy and include nodes with in the CephStorage role. For example, the following could be the content of ~/overcloud_baremetal_deploy.yaml:

- name: Controller
  count: 3
  instances:
    - hostname: controller-0
      name: controller-0
    - hostname: controller-1
      name: controller-1
    - hostname: controller-2
      name: controller-2
- name: CephStorage
  count: 3
  instances:
    - hostname: ceph-0
      name: ceph-0
    - hostname: ceph-1
      name: ceph-2
    - hostname: ceph-2
      name: ceph-2
- name: Compute
  count: 1
  instances:
    - hostname: compute-0
      name: compute-0

which is passed to the following command:

openstack overcloud node provision \
  --stack overcloud \
  --output ~/overcloud-baremetal-deployed.yaml \
  ~/overcloud_baremetal_deploy.yaml

Ceph may then be deployed with openstack overcloud ceph deploy. As described in Provisioning Baremetal Before Overcloud Deploy, pass ~/overcloud_baremetal_deploy.yaml as input, along with /usr/share/openstack-tripleo-heat-templates/environments/cephadm/cephadm.yaml and any Ceph Overrides described in the rest of this document, to the openstack overcloud deploy command.

To scale up, modify the ~/overcloud_baremetal_deploy.yaml file described above to add more CephStorage nodes. In the example below the number of storage nodes is doubled:

- name: CephStorage
  count: 6
  instances:
    - hostname: ceph-0
      name: ceph-0
    - hostname: ceph-1
      name: ceph-2
    - hostname: ceph-2
      name: ceph-2
    - hostname: ceph-3
      name: ceph-3
    - hostname: ceph-4
      name: ceph-4
    - hostname: ceph-5
      name: ceph-5

As described in Provisioning Baremetal Before Overcloud Deploy, re-run the same openstack overcloud node provision command with the updated ~/overcloud_baremetal_deploy.yaml file. This will result in the three new storage nodes being provisioned and output an updated copy of ~/overcloud-baremetal-deployed.yaml. The updated copy will have the CephStorageCount changed from 3 to 6 and the DeployedServerPortMap and HostnameMap will contain the new storage nodes.

After the three new storage nodes are deployed run the same openstack overcloud deploy command as described in the previous section with updated copy of ~/overcloud-baremetal-deployed.yaml. The additional Ceph Storage nodes will be added to the Ceph and the increased capacity will available. It is not necessary to run openstack overcloud ceph deploy to scale up.

In particular, the following will happen as a result of running openstack overcloud deploy:

  • The storage networks and firewall rules will be appropriately configured on the new CephStorage nodes

  • The ceph-admin user will be created on the new CephStorage nodes

  • The ceph-admin user’s public SSH key will be distributed to the new CephStorage nodes so that cephadm can use SSH to add extra nodes

  • If a new host with the Ceph Mon or Ceph Mgr service is being added, then the private SSH key will also be added to that node.

  • An updated Ceph spec will be generated and installed on the bootstrap node, i.e. /home/ceph-admin/specs/ceph_spec.yaml on the bootstrap node will contain new entries for the new CephStorage nodes.

  • The cephadm bootstrap process will be skipped because cephadm ls will indicate that Ceph containers are already running.

  • The updated spec will be applied and cephadm will schedule the new nodes to join the cluster.

Scenario: Scale Down Ceph with TripleO and Metalsmith

Warning

This procedure is only possible if the Ceph cluster has the capacity to lose OSDs.

Before using TripleO to remove hardware which is part of a Ceph cluster, use Ceph orchestrator to deprovision the hardware gracefully. This example uses commands from the OSD Service Documentation for cephadm to remove the OSDs, and their host, before using TripleO to scale down the Ceph storage nodes.

Start a Ceph shell and identify the OSDs to be removed by server. In the following example we will identify the OSDs of the host ceph-2:

[root@oc0-controller-0 ~]# cephadm shell
...
[ceph: root@oc0-controller-0 /]# ceph osd tree
ID  CLASS  WEIGHT   TYPE NAME            STATUS  REWEIGHT  PRI-AFF
-1         0.58557  root default
... <redacted>
-7         0.19519      host ceph-2
 5    hdd  0.04880          osd.5            up   1.00000  1.00000
 7    hdd  0.04880          osd.7            up   1.00000  1.00000
 9    hdd  0.04880          osd.9            up   1.00000  1.00000
11    hdd  0.04880          osd.11           up   1.00000  1.00000
... <redacted>
[ceph: root@oc0-controller-0 /]#

As per the example above the ceph-2 host has OSDs 5,7,9,11 which can be removed by running ceph orch osd rm 5 7 9 11. For example:

[ceph: root@oc0-controller-0 /]# ceph orch osd rm 5 7 9 11
Scheduled OSD(s) for removal
[ceph: root@oc0-controller-0 /]# ceph orch osd rm status
OSD_ID  HOST        STATE     PG_COUNT  REPLACE  FORCE  DRAIN_STARTED_AT
7       ceph-2      draining  27        False    False  2021-04-23 21:35:51.215361
9       ceph-2      draining  8         False    False  2021-04-23 21:35:49.111500
11      ceph-2      draining  14        False    False  2021-04-23 21:35:50.243762
[ceph: root@oc0-controller-0 /]#

Use ceph orch osd rm status to check the status:

[ceph: root@oc0-controller-0 /]# ceph orch osd rm status
OSD_ID  HOST        STATE                    PG_COUNT  REPLACE  FORCE  DRAIN_STARTED_AT
7       ceph-2      draining                 34        False    False  2021-04-23 21:35:51.215361
11      ceph-2      done, waiting for purge  0         False    False  2021-04-23 21:35:50.243762
[ceph: root@oc0-controller-0 /]#

Only proceed if ceph orch osd rm status returns no output.

Remove the host with ceph orch host rm <HOST>. For example:

[ceph: root@oc0-controller-0 /]# ceph orch host rm ceph-2
Removed host 'ceph-2'
[ceph: root@oc0-controller-0 /]#

Now that the host and OSDs have been logically removed from the Ceph cluster proceed to remove the host from the overcloud as described in the “Scaling Down” section of Provisioning Baremetal Before Overcloud Deploy.

Scenario: Deploy Hyperconverged Ceph

Use a command like the following to create a roles.yaml file containing a standard Controller role and a ComputeHCI role:

openstack overcloud roles generate Controller ComputeHCI -o ~/roles.yaml

The ComputeHCI role is a Compute node which also runs co-located Ceph OSD daemons. This kind of service co-location is referred to as HCI, or hyperconverged infrastructure. See the Deploying with Composable Services documentation for details on roles and services.

When collocating Nova Compute and Ceph OSD services, boundaries can be set to reduce contention for CPU and Memory between the two services. To limit Ceph for HCI, create an initial Ceph configuration file with the following:

$ cat <<EOF > initial-ceph.conf
[osd]
osd_memory_target_autotune = true
osd_numa_auto_affinity = true
[mgr]
mgr/cephadm/autotune_memory_target_ratio = 0.2
EOF
$

The osd_memory_target_autotune is set to true so that the OSD daemons will adjust their memory consumption based on the osd_memory_target config option. The autotune_memory_target_ratio defaults to 0.7. So 70% of the total RAM in the system is the starting point, from which any memory consumed by non-autotuned Ceph daemons are subtracted, and then the remaining memory is divided by the OSDs (assuming all OSDs have osd_memory_target_autotune true). For HCI deployments the mgr/cephadm/autotune_memory_target_ratio can be set to 0.2 so that more memory is available for the Nova Compute service. This has the same effect as setting the ceph-ansible is_hci parameter to true.

A two NUMA node system can host a latency sensitive Nova workload on one NUMA node and a Ceph OSD workload on the other NUMA node. To configure Ceph OSDs to use a specific NUMA node (and not the one being used by the Nova Compute workload) use either of the following Ceph OSD configurations:

  • osd_numa_node sets affinity to a numa node (-1 for none)

  • osd_numa_auto_affinity automatically sets affinity to the NUMA node where storage and network match

If there are network interfaces on both NUMA nodes and the disk controllers are NUMA node 0, then use a network interface on NUMA node 0 for the storage network and host the Ceph OSD workload on NUMA node 0. Then host the Nova workload on NUMA node 1 and have it use the network interfaces on NUMA node 1. Setting osd_numa_auto_affinity, to true, as in the initial-ceph.conf file above, should result in this configuration. Alternatively, the osd_numa_node could be set directly to 0 and osd_numa_auto_affinity could be unset so that it will default to false.

When a hyperconverged cluster backfills as a result of an OSD going offline, the backfill process can be slowed down. In exchange for a slower recovery, the backfill activity has less of an impact on the collocated Compute workload. Ceph Pacific has the following defaults to control the rate of backfill activity:

osd_recovery_op_priority = 3
osd_max_backfills = 1
osd_recovery_max_active_hdd = 3
osd_recovery_max_active_ssd = 10

It is not necessary to pass the above in an initial ceph.conf as they are the default values, but if these values need to be deployed with different values modify an example like the above and add it to the initial Ceph configuration file before deployment. If the values need to be adjusted after the deployment use ceph config set osd <key> <value>.

To limit Nova resources add parameters to ceph-overrides.yaml like the following:

parameter_defaults:
  CephHciOsdType: hdd
  CephHciOsdCount: 4

The CephHciOsdType and CephHciOsdCount parameters are used by the Derived Parameters workflow to tune the Nova scheduler to not allocate a certain amount of memory and CPU from the hypervisor to virtual machines so that Ceph can use them instead. See the Derived Parameters documentation for details. If you do not use Derived Parameters workflow, then at least set the NovaReservedHostMemory to the number of OSDs multipled by 5 GB per OSD per host.

Deploy the Ceph with openstack overcloud ceph deploy and be sure to pass the initial Ceph configuration file with Ceph HCI tunings. Then deploy the overcloud with openstack overcloud deploy and the as described in “Scenario: Deploy Ceph with TripleO and Metalsmith” but use the -r option to include generated roles.yaml file and the -e option with the ceph-overrides.yaml file containing the Nova HCI tunings described above.

The examples above may be used to tune a hyperconverged system during deployment. If the values need to be changed after deployment, then use the ceph orchestrator command to set them directly.

After deployment start a Ceph shell and confirm the above values were applied. For example, to check that the NUMA and memory target auto tuning run commands lke this:

[ceph: root@oc0-controller-0 /]# ceph config dump | grep numa
  osd                                             advanced  osd_numa_auto_affinity                 true
[ceph: root@oc0-controller-0 /]# ceph config dump | grep autotune
  osd                                             advanced  osd_memory_target_autotune             true
[ceph: root@oc0-controller-0 /]# ceph config get mgr mgr/cephadm/autotune_memory_target_ratio
0.200000
[ceph: root@oc0-controller-0 /]#

We can then confirm that a specific OSD, e.g. osd.11, inherited those values with commands like this:

[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_memory_target
4294967296
[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_memory_target_autotune
true
[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_numa_auto_affinity
true
[ceph: root@oc0-controller-0 /]#

To confirm that the default backfill values are set for the same example OSD, use commands like this:

[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_recovery_op_priority
3
[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_max_backfills
1
[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_recovery_max_active_hdd
3
[ceph: root@oc0-controller-0 /]# ceph config get osd.11 osd_recovery_max_active_ssd
10
[ceph: root@oc0-controller-0 /]#