Continental Innovates with Rancher and Kubernetes
Available as of v1.1.0
In this section, you’ll learn the requirements to prevent downtime for your applications when you upgrade the cluster using rke up.
An upgrade without downtime is one in which your workloads are available on at least a single node, and all critical addon services, such as Ingress and DNS, are available during the upgrade.
The way that clusters are upgraded changed in RKE v1.1.0. For details, refer to How Upgrades Work.
This availability is achieved by upgrading worker nodes in batches of a configurable size, and ensuring that your workloads run on a number of nodes that exceeds that maximum number of unavailable worker nodes.
To avoid downtime for your applications during an upgrade, you will need to configure your workloads to continue running despite the rolling upgrade of worker nodes. There are also requirements for the cluster architecture and Kubernetes target version.
When upgrading to a newer Kubernetes version, the upgrade must be from a minor release to the next minor version, or to within the same patch release series.
The following must be true of the cluster that will be upgraded:
The following must be true of the cluster’s applications:
For information on how to use node selectors to assign pods to nodes, refer to the official Kubernetes documentation.
For information on configuring the number of replicas for each addon, refer to this section.