Migrate Releases from Helm v2 to Helm v3¶

About this task

After upgrading a cluster, end users’ Helm releases are not upgraded from version 2. Run a custom script to migrate the end users’ Helm releases or installs to Helm v3.

Procedure

Install the /helm-2to3 plugin.

export HELM_LINTER_PLUGIN_NO_INSTALL_HOOK=true
helm plugin install /usr/local/share/helm/plugins/2to3

Fetch existing helmv2 config.

cat >get_helmv2_config.sh<<'EOF'
JSONPATH='{range .items[*]}{"\n"}{@.metadata.name}:{@.metadata.deletionTimestamp}{range @.status.conditions[*]}{":"}{@.type}={@.status}{end}{end}'
ARMADA_PODS=( $(kubectl get pods -n armada \
                --kubeconfig=/etc/kubernetes/admin.conf \
                --selector=application=armada,component=api \
                --field-selector status.phase=Running \
                --output=jsonpath="$JSONPATH") )
if [ $#ARMADA_PODS[@] -eq 0 ]; then
    echo "$NAME: ERROR - Could not find armada pod."
    exit 1
fi# Get first available Running and Ready armada pod, with tiller container
POD=""
for LINE in "$ARMADA_PODS[@]"; do
    # match only Ready pods with nil deletionTimestamp
    if [[ $LINE =~ ::.*Ready=True ]]; then
        # extract pod name, it is first element delimited by :
        A=$( cut -d ':' -f 1 - <<< "$LINE" )
        P=$A[0]
    else
        continue
    fi
    kubectl  --kubeconfig=/etc/kubernetes/admin.conf \
        cp armada/$P:tmp/.helm "$HOME"/.helm -c tiller
    RC=$?
    if [ $RC -eq 0 ]; then
        echo "$NAME: helmv2 config copied to $HOME/.helm"
        break
    else
        echo "$NAME: ERROR - failed to copy helm config from helmv2 (tiller) to host. (RETURNED: $RC)"
        exit 1
    fi
done
EOF

Move the helm2 config to helm3.

~(keystone-admin)]$ helm 2to3 move config

Choose a Helm v2 release to migrate.

~(keystone-admin)]$ helmv2-cli -- helm list -a

Migrate a helm2 release, for example, myApplication.
```
~(keystone-admin)]$ migrate_helm_release.py myApplication
```
Note

The script migrate_helm_release.py is part of the StarlingX release package.
Check if it migrated successfully.
```
~(keystone-admin)]$ helm list -A -a
```

The migrated release should not appear in helm2.

~(keystone-admin)]$ helmv2-cli -- helm list -a