Overview

Before you upgrade your service mesh components, review the following limitations and recommendations.

Revision and canary upgrade limitations

The upgrade guides in this documentation show you how to perform in-place upgrades for your Istio components, which is the recommended upgrade strategy.

Version and license requirements

  1. Verify that the minor version of the Solo distribution of Istio that you want to upgrade to is tested and supported for your Gloo Mesh version. To find the available patch versions, you can get the minor version repo URL from the Istio images built by Solo.io support article, and check the patch version builds in that repo.

  2. Check the Istio release notes for the upgrade version to prepare for any breaking changes.

  3. Be sure to review the following known Istio version restrictions.

Upgrade istioctl

  1. Save the Solo distribution of Istio patch version and tag.

      export ISTIO_VERSION=1.25.2
# Change the tags as needed
export ISTIO_IMAGE=${ISTIO_VERSION}-solo

  2. Save the repo key for the minor version of the Solo distribution of Istio that you want to install. This is the 12-character hash at the end of the repo URL us-docker.pkg.dev/gloo-mesh/istio-<repo-key>, which you can find in the Istio images built by Solo.io support article.

      # 12-character hash at the end of the minor version repo URL
export REPO_KEY=<repo_key>
export REPO=us-docker.pkg.dev/gloo-mesh/istio-${REPO_KEY}
export HELM_REPO=us-docker.pkg.dev/gloo-mesh/istio-helm-${REPO_KEY}

  3. Upgrade your istioctl CLI client to the new version.

      curl -L https://istio.io/downloadIstio | ISTIO_VERSION=${ISTIO_VERSION} sh -
cd istio-${ISTIO_VERSION}
export PATH=$PWD/bin:$PATH

Upgrade CRDs and istiod

  1. Save the name and kubeconfig context of a workload cluster in the following environment variables. Each time you repeat the steps in this guide, you change these variables to the next workload cluster’s name and context.

      export CLUSTER_NAME=<cluster-name>
export CLUSTER_CONTEXT=<cluster-context>

  2. Upgrade the Istio CRDs to the new version.

      helm get values istio-base -n istio-system -o yaml > istio-base.yaml
helm upgrade istio-base oci://${HELM_REPO}/base \
--namespace istio-system \
--version ${ISTIO_IMAGE} \
--kube-context ${CLUSTER_CONTEXT} \
-f istio-base.yaml

  3. Get the current values for the istiod Helm release in your cluster. Your release might have a different name.

      helm get values istiod -n istio-system --kube-context ${CLUSTER_CONTEXT} -o yaml > istiod.yaml
open istiod.yaml

  4. Make edits to the istiod Helm values, and save the file. If you update the Istio minor version, such as in the global.tag field, be sure to also update the value of the hub field to the repo for the correct version of the Solo distribution of Istio.

  5. Upgrade your Helm release with the updated values.

      helm upgrade istiod oci://${HELM_REPO}/istiod \
-n istio-system \
--version ${ISTIO_IMAGE} \
--kube-context ${CLUSTER_CONTEXT} \
-f istiod.yaml

  6. Verify that the istiod pods are successfully restarted. Note that it might take a few seconds for the pods to become available.

      kubectl get pods -n istio-system --context ${CLUSTER_CONTEXT} | grep istiod

    Example output:

      istiod-main-bb86b959f-msrg7   1/1     Running   0          2m45s
istiod-main-bb86b959f-w29cm   1/1     Running   0          3m

Optional: Upgrade the CNI

If you installed the Istio CNI, such as in OpenShift setups, follow the steps to upgrade this component.

  1. Get the current values for its Helm release in your cluster.

    • Kubernetes:
        helm get values istio-cni -n istio-system --kube-context ${CLUSTER_CONTEXT} -o yaml > cni.yaml
open cni.yaml
    • OpenShift:
        helm get values istio-cni -n kube-system --kube-context ${CLUSTER_CONTEXT} -o yaml > cni.yaml
open cni.yaml

  2. Make edits to the Helm values, and save the files. If you update the Istio minor version, such as in tag fields, be sure to also update the value of the hub field to the repo for the correct version of the Solo distribution of Istio.

  3. Upgrade your Helm releases with the updated values.

    • Kubernetes:
        helm upgrade istio-cni oci://${HELM_REPO}/cni -n istio-system --kube-context ${CLUSTER_CONTEXT} --version ${ISTIO_IMAGE} -f cni.yaml
    • OpenShift:
        helm upgrade istio-cni oci://${HELM_REPO}/cni -n kube-system --kube-context ${CLUSTER_CONTEXT} --version ${ISTIO_IMAGE} -f cni.yaml

  4. Verify that the Istio CNI pods are successfully restarted. Note that it might take a few seconds for the pods to become available.

    • Kubernetes:
        kubectl get pods -n istio-system --context ${CLUSTER_CONTEXT}
    • OpenShift:
        kubectl get pods -n kube-system --context ${CLUSTER_CONTEXT}

    Example output:

      istiod-main-85c4dfd97f-mncj5       1/1     Running   0             42s
istio-cni-node-pr5rl               1/1     Running   0             42s
istio-cni-node-pvmx2               1/1     Running   0             42s
istio-cni-node-lcrcd               1/1     Running   0             42s

Repeat for each cluster

Multicluster setups: Repeat the steps to upgrade CRDs and istiod and optionally upgrade the CNI for each cluster where you want to upgrade Istio. Be sure to change the values of the $CLUSTER_NAME and $CLUSTER_CONTEXT environment variables for each cluster.