Upgrading kubernetes

Upgrading kubernetes is very easy with kops, as long as you are using a compatible version of kops.The kops 1.8.x series (for example) supports the kubernetes 1.6, 1.7 and 1.8 series,as per the kubernetes deprecation policy. Older versions of kubernetes will likely still work, but theseare on a best-effort basis and will have little if any testing. kops 1.8 will not support the kubernetes1.9 series, and for full support of kubernetes 1.9 it is best to wait for the kops 1.9 series release.We aim to release the next major version of kops within a few weeks of the equivalent major release of kubernetes,so kops 1.9.0 will be released within a few weeks of kubernetes 1.9.0. We try to ensure that a 1.9 pre-release(alpha or beta) is available at the kubernetes release, for early adopters.

Upgrading kubernetes is similar to changing the image on an InstanceGroup, except that the kubernetes version iscontrolled at the cluster level. So instead of kops edit ig <name>, we kops edit cluster, and change thekubernetesVersion field. kops edit cluster will open your editor with the cluster, similar to:

  1. # Please edit the object below. Lines beginning with a '#' will be ignored,
  2. # and an empty file will abort the edit. If an error occurs while saving this file will be
  3. # reopened with the relevant failures.
  4. #
  5. apiVersion: kops/v1alpha2
  6. kind: Cluster
  7. metadata:
  8.   creationTimestamp: 2017-10-04T03:52:25Z
  9.   name: simple.k8s.local
  10. spec:
  11.   api:
  12.     loadBalancer:
  13.       type: Public
  14.   authorization:
  15.     alwaysAllow: {}
  16.   channel: stable
  17.   cloudProvider: gce
  18.   configBase: gs://kubernetes-clusters/simple.k8s.local
  19.   etcdClusters:
  20.   - etcdMembers:
  21.     - instanceGroup: master-us-central1-a
  22.       name: a
  23.     name: main
  24.   - etcdMembers:
  25.     - instanceGroup: master-us-central1-a
  26.       name: a
  27.     name: events
  28.   iam:
  29.     legacy: false
  30.   kubernetesApiAccess:
  31.   - 0.0.0.0/0
  32.   kubernetesVersion: 1.7.2
  33.   masterInternalName: api.internal.simple.k8s.local
  34.   masterPublicName: api.simple.k8s.local
  35.   networking:
  36.     kubenet: {}
  37.   nonMasqueradeCIDR: 100.64.0.0/10
  38.   project: gce-project
  39.   sshAccess:
  40.   - 0.0.0.0/0
  41.   subnets:
  42.   - name: us-central1
  43.     region: us-central1
  44.     type: Public
  45.   topology:
  46.     dns:
  47.       type: Public
  48.     masters: public
  49.     nodes: public

Edit kubernetesVersion, changing it to 1.7.7 for example.

Apply the changes to the cloud infrastructure using kops update cluster and kops update cluster --yes:

  1. Will create resources:
  2.   InstanceTemplate/master-us-central1-a-simple-k8s-local
  3.       Network                 name:default id:default
  4.       Tags                    [simple-k8s-local-k8s-io-role-master]
  5.       Preemptible             false
  6.       BootDiskImage           cos-cloud/cos-stable-57-9202-64-0
  7.       BootDiskSizeGB          64
  8.       BootDiskType            pd-standard
  9.       CanIPForward            true
  10.       Scopes                  [compute-rw, monitoring, logging-write, storage-ro, https://www.googleapis.com/auth/ndev.clouddns.readwrite]
  11.       Metadata                {cluster-name: <resource>, startup-script: <resource>}
  12.       MachineType             n1-standard-1
  14.   InstanceTemplate/nodes-simple-k8s-local
  15.       Network                 name:default id:default
  16.       Tags                    [simple-k8s-local-k8s-io-role-node]
  17.       Preemptible             false
  18.       BootDiskImage           debian-cloud/debian-9-stretch-v20170918
  19.       BootDiskSizeGB          128
  20.       BootDiskType            pd-standard
  21.       CanIPForward            true
  22.       Scopes                  [compute-rw, monitoring, logging-write, storage-ro]
  23.       Metadata                {startup-script: <resource>, cluster-name: <resource>}
  24.       MachineType             n1-standard-2
  26. Will modify resources:
  27.   InstanceGroupManager/us-central1-a-master-us-central1-a-simple-k8s-local
  28.       InstanceTemplate         id:master-us-central1-a-simple-k8s-local-1507089163 -> name:master-us-central1-a-simple-k8s-local
  30.   InstanceGroupManager/us-central1-a-nodes-simple-k8s-local
  31.       InstanceTemplate         id:nodes-simple-k8s-local-1507089694 -> name:nodes-simple-k8s-local

kops rolling-update cluster will show that all nodes need to be restarted.

  1. NAME            STATUS        NEEDUPDATE    READY    MIN    MAX    NODES
  2. master-us-central1-a    NeedsUpdate    1        0    1    1    1
  3. nodes            NeedsUpdate    3        0    3    3    3

Restart the instances with kops rolling-update cluster --yes.

  1. > kubectl get nodes -owide
  2. NAME                        STATUS    AGE       VERSION   EXTERNAL-IP     OS-IMAGE                             KERNEL-VERSION
  3. master-us-central1-a-8fcc   Ready     26m       v1.7.7    35.194.56.129   Container-Optimized OS from Google   4.4.35+
  4. nodes-9cml                  Ready     16m       v1.7.7    35.193.12.73    Ubuntu 16.04.3 LTS                   4.10.0-35-generic
  5. nodes-km98                  Ready     10m       v1.7.7    35.194.25.144   Ubuntu 16.04.3 LTS                   4.10.0-35-generic
  6. nodes-wbb2                  Ready     2m        v1.7.7    35.188.177.16   Ubuntu 16.04.3 LTS                   4.10.0-35-generic