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Distribution upgrades

This guide provides information about upgrading from one distribution release to the next.

Примечание

This guide was written when upgrading from Ubuntu Bionic to Focal during the Victoria release cycle.

Introduction

OpenStack Ansible supports operating system distribution upgrades during specific release cycles. These can be observed by consulting the operating system compatibility matrix, and identifying where two versions of the same operating system are supported.

Upgrades should be performed in the order specified in this guide to minimise the risk of service interruptions. Upgrades must also be carried out by performing a fresh installation of the target system’s operating system, before running openstack-ansible to install services on this host.

Ordering

This guide includes a suggested order for carrying out upgrades. This may need to be adapted dependent on the extent to which you have customised your OpenStack Ansible deployment.

Critically, it is important to consider when you upgrade „repo“ hosts/containers. At least one „repo“ host should be upgraded before you upgrade any API hosts/containers. The last „repo“ host to be upgraded should be the „primary“, and should not be carried out until after the final service which does not support „–limit“ is upgraded.

If this order is adapted, it will be necessary to restore some files to the „repo“ host from a backup part-way through the process. This will be necessary if no „repo“ hosts remain which run the older operating system version, which prevents older packages from being built.

Beyond these requirements, a suggested order for upgrades is a follows:

  1. Infrastructure services (Galera, RabbitMQ, APIs, HAProxy)

    In all cases, secondary or backup instances should be upgraded first

  2. Compute nodes

  3. Network nodes

Pre-Requisites

  • Ensure that all hosts in your target deployment have been installed and configured using a matching version of OpenStack Ansible. Ideally perform a minor upgrade to the latest version of the OpenStack release cycle which you are currently running first in order to reduce the risk of encountering bugs.

  • Check any OpenStack Ansible variables which you customise to ensure that they take into account the new and old operating system version (for example custom package repositories and version pinning).

  • Perform backups of critical data, in particular the Galera database in case of any failures. It is also recommended to back up the „/var/www/repo“ directory on the primary „repo“ host in case it needs to be restored mid-upgrade.

  • Identify your „primary“ HAProxy/Galera/RabbitMQ/repo infrastructure host

    In a simple 3 infrastructure hosts setup, these services/containers usually end up being all on the the same host.

    The „primary“ will be the LAST box you’ll want to reinstall.

    • HAProxy/keepalived

      Finding your HAProxy/keepalived primary is as easy as

      ssh {{ external_lb_vip_address }}
      

      Or preferably if you’ve installed HAProxy with stats, like so;

      haproxy_stats_enabled: true
      haproxy_stats_bind_address: "{{ external_lb_vip_address }}"
      

      and can visit https://admin:password@external_lb_vip_address:1936/ and read „Statistics Report for pid # on infrastructure_host“

    • repo_container

      Check all your repo_containers and look for /etc/lsyncd/lsyncd.conf.lua

Warnings

  • During the upgrade process, some OpenStack services cannot be deployed by using Ansible’s „–limit“. As such, it will be necessary to deploy some services to mixed operating system versions at the same time.

    The following services are known to lack support for „–limit“:

    • RabbitMQ

    • Repo Server

    • Keystone

  • In the same way as OpenStack Ansible major (and some minor) upgrades, there will be brief interruptions to the entire Galera and RabbitMQ clusters during the upgrade which will result in brief service interruptions.

  • When taking down „memcached“ instances for upgrades you may encounter performance issues with the APIs.

Deploying Infrastructure Hosts

  1. Drain RabbitMQ connections (optional)

    In order to cleanly hand over connections from one member of the RabbitMQ cluster to another, the instance being reinstalled should be drained. This can be achieved by running the following from the instance to be reinstalled and waiting for the RabbitMQ admin interface to indicate that socket descriptors have reduced to zero.

    rabbitmq-upgrade drain
    
  2. Disable HAProxy back ends (optional)

    If you wish to minimise error states in HAProxy, services on hosts which are being reinstalled can be set in maintenance mode (MAINT).

    Log into your primary HAProxy/keepalived and run something similar to

    echo "disable server repo_all-back/<infrahost>_repo_container-<hash>" | socat /var/run/haproxy.stat stdio
    

    for each API or service instance you wish to disable.

    Or if you’ve enabled haproxy_stats as described above, you can visit https://admin:password@external_lb_vip_address:1936/ and select them and „Set state to MAINT“

  3. Reinstall an infrastructure host’s operating system

    As noted above, this should be carried out for non-primaries first, ideally starting with a „repo“ host.

  4. Clearing out stale information

    1. Removing stale ansible-facts

      rm /etc/openstack_deploy/ansible-facts/reinstalled_host*
      

      (* because we’re deleting all container facts for the host as well.)

    2. If RabbitMQ was running on this host

      We forget it by running these commands on another RabbitMQ host.

      rabbitmqctl cluster_status
      rabbitmqctl forget_cluster_node rabbit@removed_host_rabbitmq_container
      
  5. If it is NOT a „primary“, install everything on the new host

    openstack-ansible setup-hosts.yml --limit localhost,reinstalled_host*
    openstack-ansible setup-infrastructure.yml --limit localhost,repo_all,rabbitmq_all,reinstalled_host*
    openstack-ansible setup-openstack.yml --limit localhost,keystone_all,reinstalled_host*
    

    (* because we need to include containers in the limit)

  6. If it IS a „primary“, do these steps

    openstack-ansible setup-hosts.yml --limit localhost,reinstalled_host*
    

    Temporarily set your primary Galera in MAINT in HAProxy

    openstack-ansible galera-install.yml --limit localhost,reinstalled_host*
    

    Note that at this point, the Ansible role will have taken the primary Galera out of MAINT in HAProxy. You may wish to temporarily put it back into MAINT until you are sure it is working correctly.

    You’ll now have mariadb running, but it’s not synced info from the non-primaries. To fix this we ssh to the primary Galera, and restart the mariadb.service and verify everything is in order.

    systemctl restart mariadb.service
    mysql
    mysql> SHOW STATUS LIKE "wsrep_cluster_%";
    mysql> SHOW DATABASES;
    

    Everything should be sync’ed and in order now. You can take your primary Galera from MAINT to READY

    We can move on to RabbitMQ primary

    openstack-ansible rabbitmq-install.yml
    

    The RabbitMQ primary will also be in a cluster of it’s own. You will need to fix this by running these commands on the primary.

    rabbitmqctl stop_app
    rabbitmqctl join_cluster rabbit@some_operational_rabbitmq_container
    rabbitmqctl start_app
    rabbitmqctl cluster_status
    

    Everything should now be in a working state and we can finish it off with

    openstack-ansible setup-infrastructure.yml --limit localhost,repo_all,rabbitmq_all,reinstalled_host*
    openstack-ansible setup-openstack.yml --limit localhost,keystone_all,reinstalled_host*
    
  7. Adjust HAProxy status

    If HAProxy was set into MAINT mode, this can now be removed for services which have been restored.

    For the „repo“ host, it is important that the freshly installed hosts are set to READY in HAProxy, and any which remain on the old operating system are set to „MAINT“.

Deploying Compute & Network Hosts

  1. Disable the hypervisor service on compute hosts and migrate any VMs to another available hypervisor.

  2. Reinstall a host’s operating system

  3. Clear out stale ansible-facts

    rm /etc/openstack_deploy/ansible-facts/reinstalled_host*
    

    (* because we’re deleting all container facts for the host as well.)

  4. Execute the following:

    openstack-ansible setup-hosts.yml --limit localhost,reinstalled_host*
    openstack-ansible setup-infrastructure.yml --limit localhost,reinstalled_host*
    openstack-ansible setup-openstack.yml --limit localhost,reinstalled_host*
    

    (* because we need to include containers in the limit)

Примечание

During this upgrade cycle it was noted that network nodes required a restart to bring some tenant interfaces online after running setup-openstack. Additionally, BGP speakers (used for IPv6) had to be re-initialised from the command line. These steps were necessary before reinstalling further network nodes to prevent HA Router interruptions.