Kubernetes services networking

Kuryr-Kubernetes default handler for handling Kubernetes services and endpoints uses the OpenStack Octavia API in order to have each service be implemented in the following way:

  • Service: It is translated to a single LoadBalancer and as many Listeners and Pools as ports the Kubernetes Service spec defines.

  • ClusterIP: It is translated to a LoadBalancer’s VIP.

  • loadBalancerIP: Translated to public IP associated with the LoadBalancer’s VIP.

  • Endpoints: The Endpoint object is translated to a LoadBalancer’s VIP.

Graphical depiction of the translation explained above

In this diagram you can see how the Kubernetes entities in the top left corner are implemented in plain Kubernetes networking (top-right) and in Kuryr’s default configuration (bottom)

If you are paying attention and are familiar with the Octavia API you probably noticed that we have separate pools for each exposed port in a service. This is probably not optimal and we would probably benefit from keeping a single Neutron pool that lists each of the per port listeners.

Kuryr-Kubernetes uses OpenStack Octavia as the load balancing solution for OpenStack and to provide connectivity to the Kubernetes Services.

It is beyond the scope of this document to explain in detail the inner workings of Openstack Octavia thus, only a brief explanation will be offered.

Octavia

OpenStack Octavia is a project that provides advanced Load Balancing by using pre-existing OpenStack services. The requirements for running Kuryr with OpenStack Octavia are the following:

  • Nova

  • Neutron

  • Glance

  • Barbican (if TLS offloading functionality is enabled)

  • Keystone

  • Rabbit

  • MySQL

You can find a good explanation about the involved steps to install Octavia in the Octavia installation docs.

Simplifying a lot, Octavia works by instantiating a compute resource, i.e. a Nova VM, and running HAProxy inside. These single load balancer Nova VMs are called Amphorae. Each Amphora has a separate linux network namespace where HAProxy runs and that is connected to the Kuryr services network. The VM host network namespace is used by Octavia to reconfigure and monitor the Load Balancer, which it talks to via HAProxy’s control unix domain socket.

Running Kuryr with Octavia means that each Kubernetes service that runs in the cluster will need at least one Load Balancer VM, i.e., an Amphora. To avoid single point of failure at Amphora, Octavia should be configured to support active/standby loadbalancer topology. In addition, it is important to configure the right Octavia flavor for your deployment and to size the compute nodes appropriately so that Octavia can operate well.

Another important consideration is where do the Amphorae run, i.e., whether the worker nodes should also be compute nodes so that they run the Amphorae or if Amphorae should be run separately. If your compute nodes are big enough, it would help avoiding extra hops if the amphorae were scheduled in the worker nodes, but how much significant that is, depends on your latency and throughput requirements.

Octavia uses Load Balancer drivers to handle all communications with Amphorae. By default, Kuryr-Kubernetes uses the reference Octavia driver which is the Amphora driver. Kuryr also supports the use of OVN Octavia driver.

OVN Octavia Provider Driver

Kuryr supports the creation of a load balancer with OVN provider driver. When ‘ovn’ provider is enabled as one of the Octavia Load Balancer providers, the load balancing is executed by the virtual switch data-path engine and there is no need to create VMs. This means there is no additional overhead of VMs as is required when using Octavia with the default Amphora driver.

You can find additional information about the driver, its limitations and how to create OVN-based load balancers in OVN as Provider Driver for Octavia.

Default configuration

Kuryr can use Octavia in two ways:

  • The one that is commonly referred to as Layer 3, this means that Kuryr will tell Octavia not to add a Neutron port to the pod network for each load balancer. Instead, it relies on the pod and the service subnets being routable. This means that the communication from Pods to Services and back will go through the router. Depending on the SDN of your choice, this may have performance implications.

  • The Layer 2 way, where kuryr will tell Octavia to add a Neutron port to the pod network for each load balancer. Therefore the communication from Services to its Pods members and back will go directly through L2 layer. The drawback of this approach is the extra usage of neutron ports in the Pods subnet, that needs to be accordingly dimensioned.

The services and pods subnets should be created.

  1. Create pod network:

    $ openstack network create pod
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2017-08-11T10:51:25Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | 4593045c-4233-4b4c-8527-35608ab0eaae |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1450                                 |
    | name                      | pod                                  |
    | port_security_enabled     | True                                 |
    | project_id                | 90baf12877ba49a786419b2cacc2c954     |
    | provider:network_type     | vxlan                                |
    | provider:physical_network | None                                 |
    | provider:segmentation_id  | 21                                   |
    | qos_policy_id             | None                                 |
    | revision_number           | 2                                    |
    | router:external           | Internal                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      | []                                   |
    | updated_at                | 2017-08-11T10:51:25Z                 |
    +---------------------------+--------------------------------------+
    
  2. Create pod subnet:

    $ openstack subnet create --network pod --no-dhcp \
        --gateway 10.1.255.254 \
        --subnet-range 10.1.0.0/16 \
        pod_subnet
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | allocation_pools        | 10.1.0.1-10.1.255.253                |
    | cidr                    | 10.1.0.0/16                          |
    | created_at              | 2017-08-11T10:55:25Z                 |
    | description             |                                      |
    | dns_nameservers         |                                      |
    | enable_dhcp             | False                                |
    | gateway_ip              | 10.1.255.254                         |
    | host_routes             |                                      |
    | id                      | e0a888ab-9915-4685-a600-bffe240dc58b |
    | ip_version              | 4                                    |
    | ipv6_address_mode       | None                                 |
    | ipv6_ra_mode            | None                                 |
    | name                    | pod_subnet                           |
    | network_id              | 4593045c-4233-4b4c-8527-35608ab0eaae |
    | project_id              | 90baf12877ba49a786419b2cacc2c954     |
    | revision_number         | 0                                    |
    | segment_id              | None                                 |
    | service_types           |                                      |
    | subnetpool_id           | None                                 |
    | tags                    | []                                   |
    | updated_at              | 2017-08-11T10:55:25Z                 |
    | use_default_subnet_pool | None                                 |
    +-------------------------+--------------------------------------+
    
  3. Create services network:

    $ openstack network create services
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2017-08-11T10:53:36Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | 560df0c2-537c-41c0-b22c-40ef3d752574 |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1450                                 |
    | name                      | services                             |
    | port_security_enabled     | True                                 |
    | project_id                | 90baf12877ba49a786419b2cacc2c954     |
    | provider:network_type     | vxlan                                |
    | provider:physical_network | None                                 |
    | provider:segmentation_id  | 94                                   |
    | qos_policy_id             | None                                 |
    | revision_number           | 2                                    |
    | router:external           | Internal                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      | []                                   |
    | updated_at                | 2017-08-11T10:53:37Z                 |
    +---------------------------+--------------------------------------+
    
  4. Create service subnet. We reserve the first half of the subnet range for the VIPs and the second half for the loadbalancer vrrp ports:

    $ openstack subnet create --network services --no-dhcp \
        --gateway 10.2.255.254 \
        --ip-version 4 \
        --allocation-pool start=10.2.128.1,end=10.2.255.253 \
        --subnet-range 10.2.0.0/16 \
        service_subnet
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | allocation_pools        | 10.2.128.1-10.2.255.253              |
    | cidr                    | 10.2.0.0/16                          |
    | created_at              | 2017-08-11T11:02:24Z                 |
    | description             |                                      |
    | dns_nameservers         |                                      |
    | enable_dhcp             | False                                |
    | gateway_ip              | 10.2.255.254                         |
    | host_routes             |                                      |
    | id                      | d6438a81-22fa-4a88-9b05-c4723662ef36 |
    | ip_version              | 4                                    |
    | ipv6_address_mode       | None                                 |
    | ipv6_ra_mode            | None                                 |
    | name                    | service_subnet                       |
    | network_id              | 560df0c2-537c-41c0-b22c-40ef3d752574 |
    | project_id              | 90baf12877ba49a786419b2cacc2c954     |
    | revision_number         | 0                                    |
    | segment_id              | None                                 |
    | service_types           |                                      |
    | subnetpool_id           | None                                 |
    | tags                    | []                                   |
    | updated_at              | 2017-08-11T11:02:24Z                 |
    | use_default_subnet_pool | None                                 |
    +-------------------------+--------------------------------------+
    
  5. Create a router to give L3 connectivity between the pod and the service subnets. If you already have one, you can use it:

    $ openstack router create kuryr-kubernetes
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | admin_state_up          | UP                                   |
    | availability_zone_hints |                                      |
    | availability_zones      |                                      |
    | created_at              | 2017-08-11T11:06:21Z                 |
    | description             |                                      |
    | distributed             | False                                |
    | external_gateway_info   | None                                 |
    | flavor_id               | None                                 |
    | ha                      | False                                |
    | id                      | d2a06d95-8abd-471b-afbe-9dfe475dd8a4 |
    | name                    | kuryr-kubernetes                     |
    | project_id              | 90baf12877ba49a786419b2cacc2c954     |
    | revision_number         | None                                 |
    | routes                  |                                      |
    | status                  | ACTIVE                               |
    | tags                    | []                                   |
    | updated_at              | 2017-08-11T11:06:21Z                 |
    +-------------------------+--------------------------------------+
    
  6. Create router ports in the pod and service subnets:

    $ openstack port create --network pod --fixed-ip ip-address=10.1.255.254 pod_subnet_router
    +-----------------------+---------------------------------------------------------------------------+
    | Field                 | Value                                                                     |
    +-----------------------+---------------------------------------------------------------------------+
    | admin_state_up        | UP                                                                        |
    | allowed_address_pairs |                                                                           |
    | binding_host_id       |                                                                           |
    | binding_profile       |                                                                           |
    | binding_vif_details   |                                                                           |
    | binding_vif_type      | unbound                                                                   |
    | binding_vnic_type     | normal                                                                    |
    | created_at            | 2017-08-11T11:10:47Z                                                      |
    | data_plane_status     | None                                                                      |
    | description           |                                                                           |
    | device_id             |                                                                           |
    | device_owner          |                                                                           |
    | dns_assignment        | None                                                                      |
    | dns_name              | None                                                                      |
    | extra_dhcp_opts       |                                                                           |
    | fixed_ips             | ip_address='10.1.255.254', subnet_id='e0a888ab-9915-4685-a600-bffe240dc58b' |
    | id                    | 0a82dfff-bf45-4738-a1d2-36d4ad81a5fd                                      |
    | ip_address            | None                                                                      |
    | mac_address           | fa:16:3e:49:70:b5                                                         |
    | name                  | pod_subnet_router                                                         |
    | network_id            | 4593045c-4233-4b4c-8527-35608ab0eaae                                      |
    | option_name           | None                                                                      |
    | option_value          | None                                                                      |
    | port_security_enabled | True                                                                      |
    | project_id            | 90baf12877ba49a786419b2cacc2c954                                          |
    | qos_policy_id         | None                                                                      |
    | revision_number       | 3                                                                         |
    | security_group_ids    | 2d6e006e-572a-4939-93b8-0f45b40777f7                                      |
    | status                | DOWN                                                                      |
    | subnet_id             | None                                                                      |
    | tags                  | []                                                                        |
    | trunk_details         | None                                                                      |
    | updated_at            | 2017-08-11T11:10:47Z                                                      |
    +-----------------------+---------------------------------------------------------------------------+
    
    $ openstack port create --network services \
          --fixed-ip ip-address=10.2.255.254 \
          service_subnet_router
    +-----------------------+-----------------------------------------------------------------------------+
    | Field                 | Value                                                                       |
    +-----------------------+-----------------------------------------------------------------------------+
    | admin_state_up        | UP                                                                          |
    | allowed_address_pairs |                                                                             |
    | binding_host_id       |                                                                             |
    | binding_profile       |                                                                             |
    | binding_vif_details   |                                                                             |
    | binding_vif_type      | unbound                                                                     |
    | binding_vnic_type     | normal                                                                      |
    | created_at            | 2017-08-11T11:16:56Z                                                        |
    | data_plane_status     | None                                                                        |
    | description           |                                                                             |
    | device_id             |                                                                             |
    | device_owner          |                                                                             |
    | dns_assignment        | None                                                                        |
    | dns_name              | None                                                                        |
    | extra_dhcp_opts       |                                                                             |
    | fixed_ips             | ip_address='10.2.255.254', subnet_id='d6438a81-22fa-4a88-9b05-c4723662ef36' |
    | id                    | 572cee3d-c30a-4ee6-a59c-fe9529a6e168                                        |
    | ip_address            | None                                                                        |
    | mac_address           | fa:16:3e:65:de:e5                                                           |
    | name                  | service_subnet_router                                                       |
    | network_id            | 560df0c2-537c-41c0-b22c-40ef3d752574                                        |
    | option_name           | None                                                                        |
    | option_value          | None                                                                        |
    | port_security_enabled | True                                                                        |
    | project_id            | 90baf12877ba49a786419b2cacc2c954                                            |
    | qos_policy_id         | None                                                                        |
    | revision_number       | 3                                                                           |
    | security_group_ids    | 2d6e006e-572a-4939-93b8-0f45b40777f7                                        |
    | status                | DOWN                                                                        |
    | subnet_id             | None                                                                        |
    | tags                  | []                                                                          |
    | trunk_details         | None                                                                        |
    | updated_at            | 2017-08-11T11:16:57Z                                                        |
    +-----------------------+-----------------------------------------------------------------------------+
    
  7. Add the router to the service and the pod subnets:

    $ openstack router add port \
          d2a06d95-8abd-471b-afbe-9dfe475dd8a4 \
          0a82dfff-bf45-4738-a1d2-36d4ad81a5fd
    
    $ openstack router add port \
          d2a06d95-8abd-471b-afbe-9dfe475dd8a4 \
          572cee3d-c30a-4ee6-a59c-fe9529a6e168
    
  8. Configure kuryr.conf pod subnet and service subnet to point to their respective subnets created in step (2) and (4):

    [neutron_defaults]
    pod_subnet = e0a888ab-9915-4685-a600-bffe240dc58b
    service_subnet = d6438a81-22fa-4a88-9b05-c4723662ef36
    
  9. Configure Kubernetes API server to use only a subset of the service addresses, 10.2.0.0/17. The rest will be used for loadbalancer vrrp ports managed by Octavia. To configure Kubernetes with this CIDR range you have to add the following parameter to its command line invocation:

    --service-cluster-ip-range=10.2.0.0/17
    

    As a result of this, Kubernetes will allocate the 10.2.0.1 address to the Kubernetes API service, i.e., the service used for pods to talk to the Kubernetes API server. It will be able to allocate service addresses up until 10.2.127.254. The rest of the addresses, as stated above, will be for Octavia load balancer vrrp ports. If this subnetting was not done, Octavia would allocate *vrrp* ports with the Neutron IPAM from the same range as Kubernetes service IPAM and we’d end up with conflicts.

  10. Once you have Kubernetes installed and you have the API host reachable from the pod subnet, follow the Making the Pods be able to reach the Kubernetes API section

  11. For the external services (type=LoadBalancer) case, two methods are supported:

    • Pool - external IPs are allocated from pre-defined pool

    • User - user specify the external IP address

    In case ‘Pool’ method should be supported, execute the next steps:

    1. Create an external/provider network

    2. Create subnet/pool range of external CIDR

    3. Connect external subnet to kuryr-kubernetes router

    4. Configure external network details in Kuryr.conf as follows:

      [neutron_defaults]
      external_svc_net= <id of external network>
      # 'external_svc_subnet' field is optional, set this field in case
      # multiple subnets attached to 'external_svc_net'
      external_svc_subnet= <id of external subnet>
      

    From this point for each K8s service of type=LoadBalancer and in which ‘load-balancer-ip’ is not specified, an external IP from ‘external_svc_subnet’ will be allocated.

    For the ‘User’ case, user should first create an external/floating IP:

    $ #openstack floating ip create --subnet <ext-subnet-id> <ext-netowrk-id>
    $ openstack floating ip create --subnet 48ddcfec-1b29-411b-be92-8329cc09fc12  3b4eb25e-e103-491f-a640-a6246d588561
    +---------------------------+--------------------------------------+
    | Field               | Value                                |
    +---------------------+--------------------------------------+
    | created_at          | 2017-10-02T09:22:37Z                 |
    | description         |                                      |
    | fixed_ip_address    | None                                 |
    | floating_ip_address | 172.24.4.13                          |
    | floating_network_id | 3b4eb25e-e103-491f-a640-a6246d588561 |
    | id                  | 1157e2fd-de64-492d-b955-88ea203b4c37 |
    | name                | 172.24.4.13                          |
    | port_id             | None                                 |
    | project_id          | 6556471f4f7b40e2bde1fc6e4aba0eef     |
    | revision_number     | 0                                    |
    | router_id           | None                                 |
    | status              | DOWN                                 |
    | updated_at          | 2017-10-02T09:22:37Z                 |
    +---------------------+--------------------------------------+
    

and then create k8s service with type=LoadBalancer and load-balancer-ip=<floating_ip> (e.g: 172.24.4.13)

In both ‘User’ and ‘Pool’ methods, the external IP address could be found in k8s service status information (under loadbalancer/ingress/ip)

Alternative configuration

It is actually possible to avoid this routing by performing a deployment change that was successfully pioneered by the people at EasyStack Inc. which consists of doing the following:

  1. Create the pod network and subnet so that it has enough addresses for both the pod ports and the service ports. We are limiting the allocation range out of the service range so that nor Octavia nor Kuryr-Kubernetes pod allocation create ports in the part reserved for services.

    Create the network:

    $ openstack network create k8s
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | UP                                   |
    | availability_zone_hints   |                                      |
    | availability_zones        |                                      |
    | created_at                | 2017-08-10T15:58:19Z                 |
    | description               |                                      |
    | dns_domain                | None                                 |
    | id                        | 9fa35362-0bf7-4b5b-8921-f0c7f60a7dd3 |
    | ipv4_address_scope        | None                                 |
    | ipv6_address_scope        | None                                 |
    | is_default                | False                                |
    | is_vlan_transparent       | None                                 |
    | mtu                       | 1450                                 |
    | name                      | k8s                                  |
    | port_security_enabled     | True                                 |
    | project_id                | 90baf12877ba49a786419b2cacc2c954     |
    | provider:network_type     | vxlan                                |
    | provider:physical_network | None                                 |
    | provider:segmentation_id  | 69                                   |
    | qos_policy_id             | None                                 |
    | revision_number           | 2                                    |
    | router:external           | Internal                             |
    | segments                  | None                                 |
    | shared                    | False                                |
    | status                    | ACTIVE                               |
    | subnets                   |                                      |
    | tags                      | []                                   |
    | updated_at                | 2017-08-10T15:58:20Z                 |
    +---------------------------+--------------------------------------+
    

    Create the subnet. Note that we disable dhcp as Kuryr-Kubernetes pod subnets have no need for them for Pod networking. We also put the gateway on the last IP of the subnet range so that the beginning of the range can be kept for Kubernetes driven service IPAM:

    $ openstack subnet create --network k8s --no-dhcp \
        --gateway 10.0.255.254 \
        --ip-version 4 \
        --allocation-pool start=10.0.64.0,end=10.0.255.253 \
        --subnet-range 10.0.0.0/16 \
        k8s_subnet
    +-------------------------+--------------------------------------+
    | Field                   | Value                                |
    +-------------------------+--------------------------------------+
    | allocation_pools        | 10.0.64.0-10.0.255.253               |
    | cidr                    | 10.0.0.0/16                          |
    | created_at              | 2017-08-10T16:07:11Z                 |
    | description             |                                      |
    | dns_nameservers         |                                      |
    | enable_dhcp             | False                                |
    | gateway_ip              | 10.0.255.254                         |
    | host_routes             |                                      |
    | id                      | 3a1df0d9-f738-4293-8de6-6c624f742980 |
    | ip_version              | 4                                    |
    | ipv6_address_mode       | None                                 |
    | ipv6_ra_mode            | None                                 |
    | name                    | k8s_subnet                           |
    | network_id              | 9fa35362-0bf7-4b5b-8921-f0c7f60a7dd3 |
    | project_id              | 90baf12877ba49a786419b2cacc2c954     |
    | revision_number         | 0                                    |
    | segment_id              | None                                 |
    | service_types           |                                      |
    | subnetpool_id           | None                                 |
    | tags                    | []                                   |
    | updated_at              | 2017-08-10T16:07:11Z                 |
    | use_default_subnet_pool | None                                 |
    +-------------------------+--------------------------------------+
    
  2. Configure kuryr.conf pod subnet and service subnet to point to the same subnet created in step (1):

    [neutron_defaults]
    pod_subnet = 3a1df0d9-f738-4293-8de6-6c624f742980
    service_subnet = 3a1df0d9-f738-4293-8de6-6c624f742980
    
  3. Configure Kubernetes API server to use only a subset of the addresses for services, 10.0.0.0/18. The rest will be used for pods. To configure Kubernetes with this CIDR range you have to add the following parameter to its command line invocation:

    --service-cluster-ip-range=10.0.0.0/18
    

    As a result of this, Kubernetes will allocate the 10.0.0.1 address to the Kubernetes API service, i.e., the service used for pods to talk to the Kubernetes API server. It will be able to allocate service addresses up until 10.0.63.255. The rest of the addresses will be for pods or Octavia load balancer vrrp ports.

  4. Once you have Kubernetes installed and you have the API host reachable from the pod subnet, follow the Making the Pods be able to reach the Kubernetes API section

Making the Pods be able to reach the Kubernetes API

Once you have Kubernetes installed and you have the API host reachable from the pod subnet (that means you should add 10.0.255.254 to a router that gives access to it), you should create a load balancer configuration for the Kubernetes service to be accessible to Pods.

  1. Create the load balancer (Kubernetes always picks the first address of the range we gave in –service-cluster-ip-range):

    $ openstack loadbalancer create --vip-address 10.0.0.1 \
         --vip-subnet-id 3a1df0d9-f738-4293-8de6-6c624f742980 \
         --name default/kubernetes
    +---------------------+--------------------------------------+
    | Field               | Value                                |
    +---------------------+--------------------------------------+
    | admin_state_up      | True                                 |
    | created_at          | 2017-08-10T16:16:30                  |
    | description         |                                      |
    | flavor              |                                      |
    | id                  | 84c1c0da-2065-43c5-86c9-f2235566b111 |
    | listeners           |                                      |
    | name                | default/kubernetes                   |
    | operating_status    | OFFLINE                              |
    | pools               |                                      |
    | project_id          | 90baf12877ba49a786419b2cacc2c954     |
    | provider            | octavia                              |
    | provisioning_status | PENDING_CREATE                       |
    | updated_at          | None                                 |
    | vip_Address         | 10.0.0.1                             |
    | vip_network_id      | 9fa35362-0bf7-4b5b-8921-f0c7f60a7dd3 |
    | vip_port_id         | d1182d33-686b-4bcc-9754-8d46e373d647 |
    | vip_subnet_id       | 3a1df0d9-f738-4293-8de6-6c624f742980 |
    +---------------------+--------------------------------------+
    
  2. Create the Pool for all the Kubernetes API hosts:

    $ openstack loadbalancer pool create --name default/kubernetes:HTTPS:443 \
          --protocol HTTPS --lb-algorithm LEAST_CONNECTIONS \
          --loadbalancer 84c1c0da-2065-43c5-86c9-f2235566b111
    +---------------------+--------------------------------------+
    | Field               | Value                                |
    +---------------------+--------------------------------------+
    | admin_state_up      | True                                 |
    | created_at          | 2017-08-10T16:21:52                  |
    | description         |                                      |
    | healthmonitor_id    |                                      |
    | id                  | 22ae71be-1d71-4a6d-9dd8-c6a4f8e87061 |
    | lb_algorithm        | LEAST_CONNECTIONS                    |
    | listeners           |                                      |
    | loadbalancers       | 84c1c0da-2065-43c5-86c9-f2235566b111 |
    | members             |                                      |
    | name                | default/kubernetes:HTTPS:443         |
    | operating_status    | OFFLINE                              |
    | project_id          | 90baf12877ba49a786419b2cacc2c954     |
    | protocol            | HTTPS                                |
    | provisioning_status | PENDING_CREATE                       |
    | session_persistence | None                                 |
    | updated_at          | None                                 |
    +---------------------+--------------------------------------+
    
  3. Add a member for each Kubernetes API server. We recommend setting the name to be the hostname of the host where the Kubernetes API runs:

    $ openstack loadbalancer member create \
          --name k8s-master-0 \
          --address 192.168.1.2 \
          --protocol-port 6443 \
          22ae71be-1d71-4a6d-9dd8-c6a4f8e87061
    +---------------------+--------------------------------------+
    | Field               | Value                                |
    +---------------------+--------------------------------------+
    | address             | 192.168.1.2                          |
    | admin_state_up      | True                                 |
    | created_at          | 2017-08-10T16:40:57                  |
    | id                  | 9ba24740-3666-49e8-914d-233068de6423 |
    | name                | k8s-master-0                         |
    | operating_status    | NO_MONITOR                           |
    | project_id          | 90baf12877ba49a786419b2cacc2c954     |
    | protocol_port       | 6443                                 |
    | provisioning_status | PENDING_CREATE                       |
    | subnet_id           | None                                 |
    | updated_at          | None                                 |
    | weight              | 1                                    |
    | monitor_port        | None                                 |
    | monitor_address     | None                                 |
    +---------------------+--------------------------------------+
    
  4. Create a listener for the load balancer that defaults to the created pool:

    $ openstack loadbalancer listener create \
          --name default/kubernetes:HTTPS:443 \
          --protocol HTTPS \
          --default-pool 22ae71be-1d71-4a6d-9dd8-c6a4f8e87061 \
          --protocol-port 443 \
          84c1c0da-2065-43c5-86c9-f2235566b111
    +---------------------------+--------------------------------------+
    | Field                     | Value                                |
    +---------------------------+--------------------------------------+
    | admin_state_up            | True                                 |
    | connection_limit          | -1                                   |
    | created_at                | 2017-08-10T16:46:55                  |
    | default_pool_id           | 22ae71be-1d71-4a6d-9dd8-c6a4f8e87061 |
    | default_tls_container_ref | None                                 |
    | description               |                                      |
    | id                        | f18b9af6-6336-4a8c-abe5-cb7b89c6b621 |
    | insert_headers            | None                                 |
    | l7policies                |                                      |
    | loadbalancers             | 84c1c0da-2065-43c5-86c9-f2235566b111 |
    | name                      | default/kubernetes:HTTPS:443         |
    | operating_status          | OFFLINE                              |
    | project_id                | 90baf12877ba49a786419b2cacc2c954     |
    | protocol                  | HTTPS                                |
    | protocol_port             | 443                                  |
    | provisioning_status       | PENDING_CREATE                       |
    | sni_container_refs        | []                                   |
    | updated_at                | 2017-08-10T16:46:55                  |
    +---------------------------+--------------------------------------+
    

Troubleshooting

  • Pods can talk to each other with IPv6 but they can’t talk to services.

    This means that most likely you forgot to create a security group or rule for the pods to be accessible by the service CIDR. You can find an example here:

    $ openstack security group create service_pod_access
    +-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------+
    | Field           | Value                                                                                                                                                 |
    +-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------+
    | created_at      | 2017-08-16T10:01:45Z                                                                                                                                  |
    | description     | service_pod_access                                                                                                                                    |
    | id              | f0b6f0bd-40f7-4ab6-a77b-3cf9f7cc28ac                                                                                                                  |
    | name            | service_pod_access                                                                                                                                    |
    | project_id      | 90baf12877ba49a786419b2cacc2c954                                                                                                                      |
    | revision_number | 2                                                                                                                                                     |
    | rules           | created_at='2017-08-16T10:01:45Z', direction='egress', ethertype='IPv4', id='bd759b4f-c0f5-4cff-a30a-3cd8544d2822', updated_at='2017-08-16T10:01:45Z' |
    |                 | created_at='2017-08-16T10:01:45Z', direction='egress', ethertype='IPv6', id='c89c3f3e-a326-4902-ba26-5315e2d95320', updated_at='2017-08-16T10:01:45Z' |
    | updated_at      | 2017-08-16T10:01:45Z                                                                                                                                  |
    +-----------------+-------------------------------------------------------------------------------------------------------------------------------------------------------+
    
    $ openstack security group rule create --remote-ip 10.2.0.0/16 \
         --ethertype IPv4 f0b6f0bd-40f7-4ab6-a77b-3cf9f7cc28ac
    +-------------------+--------------------------------------+
    | Field             | Value                                |
    +-------------------+--------------------------------------+
    | created_at        | 2017-08-16T10:04:57Z                 |
    | description       |                                      |
    | direction         | ingress                              |
    | ether_type        | IPv4                                 |
    | id                | cface77f-666f-4a4c-8a15-a9c6953acf08 |
    | name              | None                                 |
    | port_range_max    | None                                 |
    | port_range_min    | None                                 |
    | project_id        | 90baf12877ba49a786419b2cacc2c954     |
    | protocol          | tcp                                  |
    | remote_group_id   | None                                 |
    | remote_ip_prefix  | 10.2.0.0/16                          |
    | revision_number   | 0                                    |
    | security_group_id | f0b6f0bd-40f7-4ab6-a77b-3cf9f7cc28ac |
    | updated_at        | 2017-08-16T10:04:57Z                 |
    +-------------------+--------------------------------------+
    

    Then remember to add the new security groups to the comma-separated pod_security_groups setting in the section [neutron_defaults] of /etc/kuryr/kuryr.conf. After making the kuryr.conf edits, you need to restart the kuryr controller for the changes to take effect.

    If you want your current pods to get this change applied, the most comfortable way to do that is to delete them and let the Kubernetes Deployment create them automatically for you.