Updating Contrail Networking using the Zero Impact Upgrade Procedure in a Canonical Openstack Deployment with Juju Charms

This document provides the steps needed to update a Contrail Networking deployment that is using Canonical Openstack as it’s orchestration platform. The procedure utilizes Juju charms and provides a zero impact upgrade (ZIU) with minimal disruption to network operations.

Prerequisites

This document makes the following assumptions about your environment:

A Contrail Networking deployment using Canonical Openstack as the orchestration platform is already operational.
Juju charms for Contrail services are active in your environment, and the Contrail Networking controller has access to the Juju jumphost and the Juju cluster.

When to Use This Procedure

This procedure is used to upgrade Contrail Networking when it is running in environments using Canonical Openstack.

You can use this procedure to incrementally upgrade to the next main Contrail Networking release only. This procedure is not validated for upgrades between releases that are two or more releases apart.

The procedure in this document has been validated for the following Contrail Networking upgrade scenarios:

Table 1: Contrail Networking with Canonical Openstack Validated Upgrade Scenarios
Starting Contrail Networking Release	Target Upgraded Contrail Networking Release
Any 1912.L Release	Any 1912.L Release
1912 or any 1912.L Release	2003
2003	2005
2005	2008
2008	2011
2011	Any 2011.L Release
Any 2011.L Release	Any 2011.L Release
Any 2011 or 2011.L Release	Any 21.3 Release

Recommendations

We strongly recommend performing the following tasks before starting this procedure:

Backup your current environment.
Enable huge pages for the kernel-mode vRouter.

Starting in Contrail Networking Release 2005, you can enable huge pages in the kernel-mode vRouter to avoid future compute node reboots during upgrades. Huge pages in Contrail Networking are used primarily to allocate flow and bridge table memory within the vRouter. Huge pages for kernel-mode vRouters provide enough flow and bridge table memory to avoid compute node reboots to complete future Contrail Networking software upgrades.

We recommend allotting 2GB of memory—either using the default 1024x2MB huge page size setting or the 2x1GB size setting—for huge pages. Other huge page size settings should only be set by expert users in specialized circumstances.

A compute node reboot is required to initially enable huge pages. Future compute node upgrades can happen without reboots after huge pages are enabled. The 1024x2MB huge page setting is configured by default starting in Contrail Networking Release 2005, but is not active in any compute node until the compute node is rebooted to enable the setting.

2GB and 1MB huge page size settings cannot be enabled simultaneously in environments using Juju.

The huge page configurations can be changed by entering one of the following commands:
- Enable 1024 2MB huge pages (Default): juju config contrail-agent kernel-hugepages-2m=1024
  
  Disable 2MB huge pages (empty value): juju config contrail-agent kernel-hugepages-2m=““
- Enable 2 1GB huge pages: juju config contrail-agent kernel-hugepages-1g=2
  
  Disable 1GB huge pages (default. empty value): juju config contrail-agent kernel-hugepages-1g=““
  
  Note:
  1GB huge page settings can only be specified at initial deployment; you cannot modify the setting in active deployments. The 1GB huge page setting can also not be completely disabled after being activated on a compute node. Be sure that you want to use 1GB huge page settings on your compute node before enabling the setting.

Updating Contrail Networking in a Canonical Openstack Deployment Using Juju Charms

To update Contrail Networking in an environment that is using Canonical Openstack as the orchestration platform:

From the Juju jumphost, enter the run-action command to place all control plane services—Contrail Controller, Contrail Analytics, & Contrail AnalyticsDB—into maintenance mode in preparation for the upgrade.
Note:
The --wait option is not required to complete this step, but is recommended to ensure this procedure completes without interfering with the procedures in the next step.

Wait for all charms to move to the maintenance status. You can check the status of all charms by entering the juju status command.
Upgrade all charms. See the Upgrading applications document from Juju.

Update the image tags in Juju for the Contrail Analytics, Contrail AnalyticsDB, Contrail Agent, and Contrail Openstack services.

If a Contrail Service node (CSN) is part of the cluster, also update the image tags in Juju for the Contrail Service node.

Update the image tag in Juju for the Contrail Controller service:

After updating the image tags, wait for all services to complete stage 5 of the ZIU upgrade process workflow. The wait time for this step varies by environment, but often takes 30 to 90 minutes.

Enter the juju status command and review the Workload and Message field outputs to monitor progress. The update is complete when all services are in the maintenance state—the Workload field output is maintenance—and each individual service has completed stage 5 of the ZIU upgrade—illustrated by the ziu is in progress - stage/done = 5/5 output in the Message field.

A sample output of an in-progress update that has not completed the image tag update process. The Message field illustrates that the ZIU processes have not completed stage 5 of the upgrade.

Note:

Some juju status output fields removed for readability.

A sample output of an update that has completed the image tag update process on all services. The Workload field is maintenance for all services and the Message field explains that stage 5 of the ZIU process is done.