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Offline Microk8s installation issues

See install alternatives for offline installation of Microk8s. There are additional steps to install microk8s offline. See the following steps to install offline:

Importing images

After running the following:

snap ack microk8s_{microk8s_version}.assert
snap install microk8s_{microk8s_version}.snap --classic

You should check if the microk8s instance is healthy. Do it using the following command:

microk8s kubectl get pods -A

The output will probably look like: 

NAMESPACE      NAME                                       READY   STATUS     RESTARTS   AGE
kube-system    calico-kube-controllers-7c9c8dd885-fg8f2   0/1     Pending    0          14m
kube-system    calico-node-zg4c4                          0/1     Init:0/3   0          23s

The pods are in the Pending/Init state because they are trying to download images, which is impossible to do offline. In order to make them download, you need to download all the images on a different server with an internet connection, pack it up, and import it to a microk8s image registry on your offline server.

Packing up images for an offline environment

You need to monitor

microk8s kubectl get events -A

to see if microk8s fails to pull images, and then import anything it needs. An example of such information is:

kube-system    0s          Warning   Failed              pod/calico-node-sc784                           Failed to pull image "docker.io/calico/cni:v3.21.4": rpc error: code = Unknown desc = failed to pull and unpack image "docker.io/calico/cni:v3.21.4": failed to resolve reference "docker.io/calico/cni:v3.21.4": failed to do request: Head "https://registry-1.docker.io/v2/calico/cni/manifests/v3.21.4": dial tcp 54.83.42.45:443: i/o timeout
kube-system    0s          Warning   Failed              pod/calico-node-sc784                           Error: ErrImagePull

The previous information shows that you lack a docker.io/calico/cni:v3.21.4 image, and need to import it in order to fix the issue.

The process to do this action is always the following:

docker pull <needed_image>
docker save <needed_image> > image.tar
Transfer package to the offline lab and execute: 
microk8s ctr image import image.tar

Example of the offline installation

For example, microk8s version 3597 requires the following images to work correctly:

docker pull docker.io/calico/kube-controllers:v3.21.4 
docker pull docker.io/calico/node:v3.21.4
docker pull docker.io/calico/pod2daemon-flexvol:v3.21.4
docker pull docker.io/calico/cni:v3.21.4  
docker pull k8s.gcr.io/pause:3.1 
docker pull k8s.gcr.io/metrics-server/metrics-server:v0.5.2

You should issue the above commands on your instance connected to the internet, then save it to tar packages:

docker save docker.io/calico/kube-controllers:v3.21.4 > kube-controllers.tar
docker save docker.io/calico/node:v3.21.4 > node.tar
docker save docker.io/calico/pod2daemon-flexvol:v3.21.4 > pod2daemon-flexvol.tar
docker save docker.io/calico/cni:v3.21.4 > cni.tar
docker save k8s.gcr.io/pause:3.1  > pause.tar
docker save cdkbot/hostpath-provisioner:1.2.0 > cdkbot.tar 
docker save k8s.gcr.io/metrics-server/metrics-server:v0.5.2 > metrics.tar

After that, scp those packages to your offline server and import it to its microk8s image registry:

microk8s ctr image import kube-controllers.tar
microk8s ctr image import node.tar
microk8s ctr image import pod2daemon-flexvol.tar
microk8s ctr image import cni.tar
microk8s ctr image import pause.tar
microk8s ctr image import metrics.tar

Info

For other versions of microk8s, tags of images may differ.

After running the following:

microk8s enable hostpath-storage
microk8s enable rbac
microk8s enable metrics-server

The microk8s instance should be the following:

NAMESPACE      NAME                                       READY   STATUS                  RESTARTS   AGE
kube-system    calico-kube-controllers-7c9c8dd885-wxms9   1/1     Running                 0          3h21m
kube-system    calico-node-8cxsq                          1/1     Running                 0          3h21m
kube-system    hostpath-provisioner-f57964d5f-zs4sj       1/1     Running                 0          5m41s
kube-system    metrics-server-5f8f64cb86-x7k29            1/1     Running                 0          2m15s

Enabling DNS and Metallb

dns and metallb do not require importing any images, so you can enable them simply through the following commands:

microk8s enable dns
microk8s enable metallb

For more information on metallb, see Install metallb.

Installing helm3

Additionally, you need to install the helm3 add-on. See the following steps:

  1. Check your server’s platform with:
dpkg --print-architecture

The output would be, for example: amd64. You need the platform to download the correct version of helm.

  1. Download the helm package from https://get.helm.sh/helm-v3.8.0-linux-{{arch}}.tar.gz, where {{arch}} should be replaced with the result from the previous command, for example: https://get.helm.sh/helm-v3.8.0-linux-amd64.tar.gz.

  2. Rename the package to helm.tar.gz and send it to an offline lab.

  3. Create tmp directory in /var/snap/microk8s/current and copy the package in the following locations: 
sudo mkdir -p /var/snap/microk8s/current/tmp/helm3
sudo cp helm.tar.gz /var/snap/microk8s/current/tmp/helm3
  1. Go to the directory containing enable script for helm3:
cd /var/snap/microk8s/common/addons/core/addons/helm3

Open enable file with vi, nano, or some other editor. Comment this line:

#fetch_as $SOURCE_URI/helm-$HELM_VERSION-linux-${SNAP_ARCH}.tar.gz "$SNAP_DATA/tmp/helm3/helm.tar.gz"

Save file.

  1. Run microk8s enable helm3

Verify your instance

Check if all the add-ons were installed successfully using the following command: microk8s status --wait-ready. An example of a correct output is:

microk8s is running
high-availability: no
  datastore master nodes: 127.0.0.1:19001
  datastore standby nodes: none
addons:
  enabled:
    dns                  # (core) CoreDNS
    ha-cluster           # (core) Configure high availability on the current node
    helm3                # (core) Helm 3 - Kubernetes package manager
    hostpath-storage     # (core) Storage class; allocates storage from host directory
    metallb              # (core) Loadbalancer for your Kubernetes cluster
    metrics-server       # (core) K8s Metrics Server for API access to service metrics
    rbac                 # (core) Role-Based Access Control for authorisation
    storage              # (core) Alias to hostpath-storage add-on, deprecated
  disabled:
    community            # (core) The community addons repository
    dashboard            # (core) The Kubernetes dashboard
    gpu                  # (core) Automatic enablement of Nvidia CUDA
    helm                 # (core) Helm 2 - the package manager for Kubernetes
    host-access          # (core) Allow Pods connecting to Host services smoothly
    ingress              # (core) Ingress controller for external access
    mayastor             # (core) OpenEBS MayaStor
    prometheus           # (core) Prometheus operator for monitoring and logging
    registry             # (core) Private image registry exposed on localhost:32000