f7ce1912f7
Removing superfluous documentation as well as moving changing doc structure to better reflect contents of documentation. Change-Id: I6fa798b9c6fc542ef05c954acae8641f69f5cb2b
1.3 KiB
Pod Disruption Budgets
OpenStack-Helm leverages PodDistruptionBudgets to enforce quotas that ensure that a certain number of replicas of a pod are available at any given time. This is particularly important in the case when a Kubernetes node needs to be drained.
These quotas are configurable by modifying the
minAvailable field within each PodDistruptionBudget
manifest, which is conveniently mapped to a templated variable inside
the values.yaml file. The min_available within
each service's values.yaml file can be represented by
either a whole number, such as 1, or a percentage, such as
80%. For example, when deploying 5 replicas of a pod (such
as keystone-api), using min_available: 3 would enfore
policy to ensure at least 3 replicas were running, whereas using
min_available: 80% would ensure that 4 replicas of that pod
are running.
Note: The values defined in a PodDisruptionBudget
may conflict with other values that have been provided if an operator
chooses to leverage Rolling Updates for deployments. In the case where
an operator defines a maxUnavailable and
maxSurge within an update strategy that is higher than a
minAvailable within a pod disruption budget, a scenario may
occur where pods fail to be evicted from a deployment.