ConfD Upgrade Considerations

CommunityTo upgrade or not to upgrade, this is the constant question IT teams and network device makers consider regularly. Update cycles can sometimes feel like a reoccurring churn being driven by the need to deliver better capabilities or services to the customer. But don’t be fooled, it is a necessary evil as better capabilities like programmability and automation drive what’s new and possible in the market. The real question is how long can you wait till you need to upgrade?

In network management, software upgrades can be the riskiest operations and if not done right, can bring down a whole network by modifying something that shouldn’t be modified, such as configuration, or, even worse, by losing an entire customer configuration. A well-planned strategy for upgrades is needed to cover all corner cases and ensure an operational network post-upgrade.

For ConfD, there are several points that should be considered before upgrading. First of all, we should differentiate between the different types of upgrades that have to do with the management layer. There is a ConfD daemon upgrade, which upgrades the ConfD version, there is a ConfD client upgrade, which upgrades the ConfD library used by applications to talk to ConfD, which is always needed when we upgrade ConfD, and there is the schema upgrade which is tied to YANG data model changes and is independent of ConfD upgrades.

Depending on what is being upgraded, there are different considerations to take into account.

For example, when upgrading the database schema, which means new or modified YANG modules were introduced, we should consider backward compatibility and preserving the customer configuration data. If our schema change is non-backward compatible, what can we do to preserve the configuration?

If the ConfD daemon is upgraded, alone or with a schema upgrade, another set of potential issues are to be considered.

For more information on issues to consider when upgrading ConfD and how to properly conduct the upgrade operation in production, please, read our application note “Upgrading ConfD and the CDB Schema