Mesosphere Kubernetes Engine

The kubernetes CLI provides an option that allows for easier updates to a service’s configuration and version of the manager, as well as allowing users to inspect the status of updates, to pause and resume updates, and to restart or complete steps if necessary.

Updating the manager version

Before starting the update process, it is mandatory to update the kubernetes CLI to the new version:

dcos package install kubernetes --cli --package-version=NEW-VERSION

To update the manager, the dcos kubernetes manager update start --package-version=PACKAGE-VERSION subcommand is available.

$  dcos kubernetes manager update start -h
Launches an update operation

Flags:
    --options=OPTIONS  Path to a JSON file that contains customized package installation options, or 'stdin' to read from stdin
    --package-version=PACKAGE-VERSION
                       The desired package version
    --replace          Replace the existing configuration in whole. Otherwise, the existing configuration and options are merged.

Updating the manager options

To update the service configuration of the Mesosphere Kubernetes Engine, e.g. to increase the CPU or memory resources to mesosphere_kubernetes_engine. As an example, we will describe how to achieve the latter.

1. Assuming you have configured the Mesosphere Kubernetes Engine with its default options, all that is required is creating a new_options.json file with the following contents:

{
  "mesosphere_kubernetes_engine": {
    "cpus": 0.5,
    "mem": 1024
  }
}

2. Run:

dcos kubernetes manager update start --options=new_options.json

Kubernetes Cluster

Before you start, keep in mind that updating the cluster may trigger a restart of a subset or all the components managed by this framework, depending on whether new versions of these components or related ones are part of the new release.

Updating these components means the Kubernetes cluster may experience some downtime or, in the worst-case scenario, cease to function properly. And while we are committed to make the user experience as robust and smooth as possible, in fact is there is no such thing as fail-proof software.

IMPORTANT: Before updating the cluster version, proceed cautiously and always back up your data.

In the future, we will be integrating the disaster-recovery functionality so you can easily revert to the previous functioning state.

Updating the version vs updating cluster options

When a new version is available, you will have the option to update to the new version. If you have not updated the version in a while, it may be that an update to the most recent version is not allowed and you will be informed on how to proceed.

However, you may only want to update the options, for example, in order to change the resources allocated to one type of Kubernetes component. Keep in mind that options updates may also mean the Kubernetes cluster may experience some downtime or, in the worst-case scenario, cease to function properly.

IMPORTANT: Before updating the options, proceed cautiously and always back up your data.

Updating the cluster version

Before starting the update process, it is mandatory to update the kubernetes CLI to the new version:

dcos package install kubernetes --cli --package-version=NEW-VERSION

The version upgrade is only supported on DC/OS Enterprise Edition. To update the cluster version, the dcos kubernetes cluster update --cluster-name=CLUSTER-NAME subcommand is available.

$ dcos kubernetes cluster update --cluster-name=CLUSTER-NAME -h
usage: dcos kubernetes cluster update --cluster-name=CLUSTER-NAME [<flags>]

Flags:
  -h, --help             Show context-sensitive help.
  -v, --verbose          Enable extra logging of requests/responses
      --version          Show application version.
      --cluster-name=CLUSTER-NAME
                         Name of the Kubernetes cluster
      --options=OPTIONS  Path to a JSON file containing the target package options
      --package-version=PACKAGE-VERSION
                         The target package version
      --yes              Do not ask for confirmation before starting the update process
      --force            Force the update operation

IMPORTANT: Due to the number of variables such as the DC/OS cluster resources available, CPU and internet speed, etc., the installer cannot automatically determine a proper --timeout value and is recommended to increase it when updating larger clusters.

Starting the cluster version update:

$ dcos kubernetes cluster update  --cluster-name=CLUSTER-NAME --package-version=NEW-VERSION
About to start an update from version CURRENT-VERSION to NEW-VERSION

Updating these components means the Kubernetes cluster may experience some downtime or, in the worst-case scenario, cease to function properly. Before updating proceed cautiously and always back up your data.

This operation is long-running and has to run to completion.
Are you sure you want to continue? [yes/no] yes

Starting upgrade process...
Upgrade is in progress. Check status of deploy plan for more information.

Updating the cluster options

This service exposes certain options that advanced users can use to adapt the Kubernetes cluster to their need. For instance, you may want to increase the kube-apiserver count or the resources available to kube-proxy. As an example, we will describe how to achieve the latter.

1. Assuming you have installed the cluster with its default options, all that is required is creating a new_options.json file with the following contents:

{
  "kube_proxy": {
    "cpus": 0.5,
    "mem": 1024
  }
}

2. Run:

dcos kubernetes cluster update --cluster-name=CLUSTER-NAME --options=new_options.json

Here is the expected output:

The following differences were detected between service configurations (CHANGED, CURRENT):
 ==  {
 ==  "kube_proxy": {
 -      "cpus": 0.1,
 +      "cpus": 0.5,
 -      "mem": 512,
 +      "mem": 1024,
 ==  }
 == }

The components of the cluster will be updated according to the changes in the options file [new_options.json].

Updating these components means the Kubernetes cluster may experience some downtime or, in the worst-case scenario, cease to function properly.
Before updating proceed cautiously and always back up your data.

This operation is long-running and has to run to completion.
Are you sure you want to continue? [yes/no] yes

Starting update process...
Update is in progress. Check status of deploy plan for more information.

Some options are special in the sense that they must only ever be updated once after cluster installation, and only towards a specific target value. Also, some options must not be changed at all after the cluster is installed for the first time.

These options are:

Please make sure you understand and respect these rules. Otherwise you may render your cluster unusable and risk losing data.

Note that, whenever any invalid configuration is provided, the Kubernetes service scheduler might enter into a crash loop. To revert these changes you will need to use the flag --force. This flag will overwrite the service configuration with the new settings.

dcos kubernetes cluster update --cluster-name=CLUSTER-NAME --options=new_options.json --force