The release notes include important installation changes and known issues. They also highlight ways that you can take advantage of new features or enhancements to improve your product usage.

For more information, see the following related resources:

  • Changelog: A full list of changes, including the ability to compare previous patch and minor versions.
  • Upgrade guide: Steps to upgrade from the previous minor version to the current version.
  • Version reference: Information about Solo’s version support.

đŸ”Ĩ Breaking changes

Review details about the following breaking changes. To review when breaking changes were released, you can use the comparison feature of the changelog. The severity is intended as a guide to help you assess how much attention to pay to this area during the upgrade, but can vary depending on your environment.

🚨 High

Review severe changes that can impact production and require manual intervention.

  • Automatic resource validation: A new feature that validates Gloo custom resources. This feature is enabled by default. Invalid resources do not block the upgrade. However, after the upgrade, you cannot make any changes to your invalid resources until the errors are resolved. This can block development of or updates to your existing Gloo resources.
  • Istio 1.21 support - JWT policy translation: Translation for authorization-related fields, such as requiredScopes or claims changed. If you plan to use JWT policies with Istio 1.21, you must follow the upgrade steps to safely re-create existing EnvoyFilters. If not, routes that are protected by JWT policies might fail open.

🔔 Medium

Review changes that might have impact to production and require manual intervention, but possibly not until the next version is released.

ℹī¸ Low

Review informational updates that you might want to implement but that are unlikely to materially impact production.

  • Upstream Prometheus Helm chart upgrade: The Prometheus Helm chart version is upgraded to a newer version, which requires the Prometheus deploymented to be re-created. Gloo Mesh Gateway uses a Helm pre-upgrade hooks to re-create the deployment which can cause issues in automated environments, such as Argo CD.

Automatic resource validation

In Gloo Mesh Gateway 2.6 and later and Kubernetes 1.25 and later, the fields of select Gloo CRDs contain constraints and rules to ensure that only valid configuration is admitted to your Gloo setup. This feature is enabled by default to ensure that any attempt to apply invalid configuration to your cluster is rejected. To see the constraints and rules for each field, check the API reference docs for each custom resource and look for the Configuration constraints. For more information, see the resource validation overview.

If you have invalid resources that you do not fix before you upgrade, you can still complete the upgrade to 2.6. However, after the upgrade, you cannot make any changes to your invalid resources until the errors are resolved. This can block development of or updates to your existing Gloo resources.

Before you upgrade to 2.6, complete the following steps to ensure that your 2.5 Gloo CRs are valid according to the rules that are enforced in 2.6.

  1. Update meshctl to the 2.6 patch version you want to upgrade to.

  2. Run the following command to validate your existing resources. For more information, see the CLI command reference.

      meshctl x validate resources --context $MGMT_CONTEXT
  3. Check the Resource Errors & Warnings section of the output for any errors in your CRs. In this example output, one error is reported for the ExtAuthPolicy resource named workload-00014-portal-rt-delegate-api in the gloo-mesh-addons namespace. Warnings are also reported for Service and VirtualDestination resources, but note that warnings do not prevent resources from being applied.

    Resource Errors & Warnings
    | Cluster   | Kind               | Ns/Name                                                                                  | Errors | Warnings |
    | --------------------------------------------------------------------------------------------------------------------------------------------- |
    | cluster-1 | Service            | workload-00019-cluster-1/workload-00019                                                  | 0      | 25       |
    | --------------------------------------------------------------------------------------------------------------------------------------------- |
    | cluster-1 | VirtualDestination | workload-00014-cluster-1/workload-00014-portal-cluster-1-692abccf4324f8554e3a4dc66077734 | 0      | 25       |
    | --------------------------------------------------------------------------------------------------------------------------------------------- |
    | cluster-1 | ExtAuthPolicy      | gloo-mesh-addons/workload-00014-portal-rt-delegate-api                                   | 1      | 0        |
    | --------------------------------------------------------------------------------------------------------------------------------------------- |
    Saved to /var/folders/b5/9rwm6sld7w3bw7q0wnnd0ym40000gn/T/validate-logs/input-resource-errors.json
  4. If errors are reported:

    1. Check the errors by opening the generated input-resource-errors.json file, such as /var/folders/b5/9rwm6sld7w3bw7q0wnnd0ym40000gn/T/validate-logs/input-resource-errors.json in the example output of the previous step.
    2. Update your resources to fix the invalid fields. To review the constraints and rules for each field, check the API reference docs for each custom resource and look for the Configuration constraints.
    3. Run the validation checks on your updated resource YAML files.
        meshctl x validate resources <updated-resources>.yaml
    4. Apply the updated, valid resources to your management cluster.
  5. After you confirm that all resources are valid and that no errors are reported, proceed to upgrade your Gloo Mesh Gateway installation.

Istio 1.21 support

JWT policy translation:

Gloo Mesh Gateway version 2.6 now supports Istio version 1.21. To support Istio 1.21, the translation of JWTPolicy custom resources into EnvoyFilters changed. If you currently use Gloo JWT policies in your environment that configure authorization-related fields, such as requiredScopes or claims and you plan to upgrade to Istio 1.21, you must upgrade the Gloo management server to version 2.6 first. Upgrading the management server ensures that the translation logic for JWTPolicy custom resources is updated and that the Gloo management server re-generates existing EnvoyFilters to make them compatible with Istio version 1.21.

To upgrade your Gloo Mesh Gateway version, see the Upgrade docs.

New Helm defaults for Solo image repositories

The default Helm values for the Solo images changed from to For example, the Redis image changed from to If you internal tooling is set up to pull the images from, such as in air-gapped environments, you must update that tooling to pull the images from the Google Cloud Registry repository.

For an overview of the images that are used in an air-gapped environment, see the Install in air-gapped environments docs in the Gloo Mesh Enterprise documentation.

Upstream Prometheus upgrade

Gloo Mesh Gateway includes a built-in Prometheus server to help monitor the health of your Gloo components. This release of Gloo upgrades the Prometheus community Helm chart from version 19.7.2 to 25.11.0. As part of this upgrade, upstream Prometheus changed the selector labels for the deployment, which requires recreating the deployment. To help with this process, the Gloo Helm chart includes a pre-upgrade hook that automatically recreates the Prometheus deployment during a Helm upgrade. This breaking change impacts upgrades from previous versions to version 2.4.10, 2.5.1, or 2.6.0 and later.

If you do not want the redeployment to happen automatically, you can disable this process by setting the prometheus.skipAutoMigration Helm value to true. For example, you might use Argo CD, which converts Helm pre-upgrade hooks to Argo PreSync hooks and causes issues. To ensure that the Prometheus server is deployed with the right version, follow these steps:

  1. Confirm that you have an existing deployment of Prometheus at the old Helm chart version of chart: prometheus-19.7.2.
      kubectl get deploy -n gloo-mesh prometheus-server -o yaml | grep chart
  2. Delete the Prometheus deployment. Note that while Prometheus is deleted, you cannot observe Gloo performance metrics.
      kubectl delete deploy -n gloo-mesh prometheus-server
  3. In your Helm values file, set the prometheus.skipAutoMigration field to true.
  4. Continue with the Helm upgrade of Gloo Mesh Gateway. The upgrade recreates the Prometheus server deployment at the new version.

⚒ī¸ Installation changes

In addition to comparing differences across versions in the changelog, review the following installation changes from the previous minor version to version 2.6.

Safe mode enabled by default

Starting in version 2.6.0, safe mode is enabled on the Gloo management server by default to ensure that the server translates input snapshots only if all input snapshots are present in Redis or its local memory. This way, translation only occurs based on a complete translation context that includes all workload clusters.

Enabling safe mode resolves a race condition that was identified in version 2.5.3, 2.4.11, and earlier that could be triggered during simultaneous restarts of the management plane and Redis, including an upgrade to a newer Gloo Mesh Enterprise version. If hit, this failure mode could lead to partial translations on the Gloo management server which could result in Istio resources being temporarily deleted from the output snapshots that are sent to the Gloo agents.

To learn more about safe mode, see Safe mode.

New default values for Gloo UI auth sessions

Some of the default Helm values changed for configuring the Gloo UI auth session storage:

  • glooUi.auth.oidc.session.backend: The default value changed from "" (empty) to cookie to ensure auth sessions are stored in browser cookies by default.
  • The default value changed from "" (empty) to gloo-mesh-redis.gloo-mesh:6379 to ensure a valid Redis host is set when glooUi.auth.oidc.session.backend is changed to redis.

To learn how to set up Gloo UI auth session storage, see Store UI sessions.

New container settings for Redis

In 2.6, the default container settings for the built-in Redis changed. To apply these settings, Redis must be restarted during the upgrade. Make sure that safe mode is enabled before you proceed with the upgrade so that translation of input snapshots halts until the input snapshots of all connected Gloo agents are re-populated in Redis. In 2.6.0, safe mode is enabled by default.

To learn more about safe mode, see Safe mode.

🌟 New features

Review the following new features that are introduced in version 2.6 and that you can enable in your environment.

Istio 1.21 and 1.22 support

Starting in version 2.6.0, you can now use Istio 1.21 and 1.22. Note that you must upgrade the Gloo management server to version 2.6 first before you start upgrading your Istio version. To find the image reposititories for the Solo distribution of Istio, see the Istio images built by Solo support article. Istio versions 1.16 and 1.17 are no longer supported in 2.6.

For more information about supported Kubernetes and Istio versions, see the version support matrix.

Kubernetes 1.29 and 1.30 support

Starting in version 2.6.0, Gloo Mesh Gateway can now run on Kubernetes 1.29 and 1.30. Kubernetes version 1.22 and 1.23 are no longer supported. For more information about supported Kubernetes and Istio versions, see the version support matrix.

I/O threads for Redis

A new Helm value redis.deployment.ioThreads was introduced to specify the number of I/O threads to use for the built-in Redis instance. Redis is mostly single threaded, however some operations, such as UNLINK or slow I/O accesses can be performed on side threads. Increasing the number of side threads can help improve and maximize the performance of Redis as these operations can run in parallel.

If you set I/O threads, the Redis pod must be restarted during the upgrade so that the changes can be applied. During the restart, the input snapshots from all connected Gloo agents are removed from the Redis cache. If you also update settings in the Gloo management server that require the management server pod to restart, the management server’s local memory is cleared and all Gloo agents are disconnected. Although the Gloo agents attempt to reconnect to send their input snapshots and re-populate the Redis cache, some agents might take longer to connect or fail to connect at all. To ensure that the Gloo management server halts translation until the input snapshots of all workload cluster agents are present in Redis, it is recommended to enable safe mode on the management server alongside updating the I/O threads for the Redis pod. For more information, see Safe mode. Note that in version 2.6.0 and later, safe mode is enabled by default.

To update I/O side threads in Redis as part of your Gloo Mesh Enterprise upgrade:

  1. Scale down the number of Gloo management server pods to 0.

      kubectl scale deployment gloo-mesh-mgmt-server --replicas=0 -n gloo-mesh
  2. Upgrade Gloo Mesh Enterprise and use the following settings in your Helm values file for the management server. Make sure to also increase the number of CPU cores to one core per thread, and add an additional CPU core for the main Redis thread. The following example also enables safe mode on the Gloo management server to ensure translation is done with the complete context of all workload clusters.

      safeMode: true
        ioThreads: 2
            cpu: 3
            cpu: 3

Gloo insights and improved UI

In version 2.6.0 and later, Gloo Mesh Gateway comes with an insights engine that automatically analyzes your Istio setups for health issues. Then, Gloo shares these issues along with recommendations to harden your Istio setups. The insights give you a checklist to address issues that might otherwise be hard to detect across your environment. Note that in large-scale environments, allotting additional resources to the engine and analyzer components is recommended. For an overview of available insights and more information, see Insights.

To enable insights generation, you must include the following settings when you upgrade your Helm installations:

  • --set glooInsightsEngine.enabled=true in your management cluster
  • --set glooAnalyzer.enabled=true in each workload cluster

Consider deploying a dedicated Redis instance to store insights data, which is recommended to separate observability data from the snapshot data that the Redis instance for your management server stores. You can enable a Gloo-managed Redis instance for the insights engine by including the --set redisStore.insights.deployment.enabled=true setting in your management cluster when you upgrade your Gloo Mesh Gateway installation. For a more secure setup, you can instead bring your own Redis instance, and use the --set redisStore.insights.client.address=<external_redis_address> setting to point to the external address of your Redis instance. For more information, see Backing databases.

Figure: Insights page

Additionally, when you enable insights in your Gloo Mesh Gateway installation, the Gloo UI is updated with an improved Dashboard to help you quickly review the health and status of your environment. To review the new features, see Explore the new UI with insights.

Figure: Gloo UI dashboard

Persistence mode for built-in Redis

To back up data for the Gloo Mesh Gateway control plane components like the management server, you can use a Solo-provided built-in Redis instance that is installed in the cluster. By default, this built-in Redis instance does not persist data, which gets lost during pod restarts. Now, you can also configure the built-in Redis to use persistent storage. This way, data persists across Redis restarts, such as after an upgrade. By persisting the data, you can reduce delays in the relay process that otherwise would happen after a restart. For more information, see Persistent storage.

New feature gate for VirtualDestinationWorkspacePolicyOverride

Previous, virtual destinations that were imported from a source workspace to a target workspace kept the client-side attached policies from the source workspace. Also, when a virtual destination was backed by services on the same host that had different policies attached, the applied policy could be unpredictable.

Now, when you enable the VirtualDestinationWorkspacePolicyOverride feature gate, these policy behaviors are changed to improve consistency and client-side control.

Imported virtual destinations still keep their client-side attached policies from the source workspace. However, you as the target workspace owner can apply your own client-side policies to override the policies from the source workspace. This way, each team can set its own policies for the virtual destination within their own workspace, but share the virtual destination configuration across teams.

Additionally, underlying services behind a virtual destination now can use subset routing. After enabling the feature gate, this feature automatically works in scenarios where you have overriding policies that apply to a virtual destination that is imported across workspaces. This way, services in different workspaces that use the same virtual destination host can have distinct client-side policies where applicable, such as for failover traffic.

  1. Determine whether you need to enable the VirtualDestinationWorkspacePolicyOverride feature gate. With the feature gate enabled, you can override client-side policies when importing virtual destinations from a source workspace in to a target workspace. This way, you can apply your own client-side policies in the importing target workspace. Client-side policies include the following. For more information, see the Import and export policies conceptual overview.
    • ActiveHealthCheckPolicy
    • AdaptiveRequestConcurrencyPolicy
    • ClientTLSPolicy
    • ConnectionPolicy for TCP
    • FailoverPolicy
    • LoadBalancerPolicy
    • OutlierDetectionPolicy
  2. Assess the impact to your setup if you enable the feature gate.
    • Any virtual destinations that currently have client-side policies experience dropped traffic until all the configuration changes propagate across clusters.
    • Configuration changes include the underlying Istio resources that are created for the policies. In particular, previously a single Istio DestinationRule per policy was created and used by the importing namespaces. Now, an Istio DestinationRule is created per namespace, increasing the number of underlying resources that are propagated.
    • After the upgrade, the underlying EnvoyFilters use subset routing, which means that they have entries per client, inside of a single entry per shared virtual destination host.
  3. Continue with the upgrade by including the featureGates.VirtualDestinationWorkspacePolicyOverride=true setting. For more information, see the Feature gates reference docs.

🔄 Feature changes

Review the following changes that might impact how you use certain features in your Gloo environment.

Improved error logging

The Gloo management server translates your Gloo custom resources into many underlying Istio resources. When the management server cannot translate a resource, it returns debug logs that vary in severity from errors to warnings or info.

In this release, the management server logs are improved in the following ways:

  • All translation errors are now logged at the debug level. This way, the management server logs are not cluttered by errors that do not impact the management server’s health.
  • Fixed a bug that caused many duplicate error logs. Now, you have fewer logs to sift through.

For example, you might have a service that does not select any existing workloads. This scenario might be intentional, such as if you use a CI/CD tool like ArgoCD to deploy your environment in phases. Translation does not complete until you update the service’s selector or create the workload. Previously, the translation error would show up many times in the management server logs, even though the situation is intentional and the management server is healthy and can translate other objects. Now, the translation error is logged less verbosely at the debug level.

You can still review translation errors in the following ways:

  • Translation errors and warnings are shown in the statuses of Gloo custom resources. For example, if a policy fails to apply to a route, you can review the warning in the policy and the route table statuses.
  • In the management server, enable debug logging by enabling the --verbose=true setting. Example command:
      kubectl patch deploy -n gloo-mesh gloo-mesh-mgmt-server --type "json" -p '[{"op":"add","path":"/spec/template/spec/containers/0/args/-","value":"--verbose=true"}]'

Improved external service routing

Now, you can create multiple external services that share the same host but have different ports or wildcard subdomains. For example, you might have different teams own different subdomains of an external service. Or, several third-party services might be exposed on different ports of the same host. Previously, creating multiple external services with a conflicting wildcard host or a different port on the same host was not supported. For more information, see Route to external services.

Istio resources not generated on non-mesh clusters

Added a fix that now prevents Istio resources from being written to the management cluster when the management cluster is not registered as a workload cluster at the same time. Previously, if you had an Istio installation in your management cluster that was not managed by Gloo Mesh Gateway and a Gloo agent was deployed to that cluster at the same time, the agent discovered these Istio resources and included them in the snapshot that was sent to the management server. The agent also wrote Istio resources to that cluster, which might have inteferred with existing Istio resources in that cluster.

Previously generated resources are not automatically removed during the upgrade. You must manually clean up these resources in the management cluster. You can use the following script to remove these resources.



if [ -z "$namespace" ]; then
  echo "Usage: <namespace>"
  exit 1

kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete -n $namespace -l ""
kubectl delete  -n $namespace -l ""

🚧 Known issues

The Solo team fixes bugs, delivers new features, and makes changes on a regular basis as described in the changelog. Some issues, however, might impact many users for common use cases. These known issues are as follows:

  • Cluster names: Do not use underscores (_) in the names of your clusters or in the kubeconfig context for your clusters.

  • OTel pipeline: FIPS-compliant builds are not currently supported for the OTel collector agent image.

  • Istio:

    • Due to a lack of support for the Istio CNI and iptables for the Istio proxy, you cannot run Istio (and therefore Gloo Mesh Gateway) on AWS Fargate. For more information, see the Amazon EKS issue.
    • In Istio 1.22, the ISTIO_DELTA_XDS environment variable must be set to false. For more information, see this upstream Istio issue.
    • If you plan to upgrade to Istio 1.21, you must upgrade the Gloo management server to version 2.6 first. For more information, see the 2.6 release notes.
    • Istio 1.20 is supported only as patch version 1.20.1-patch1 and later. Do not use patch versions 1.20.0 and 1.20.1, which contain bugs that impact several Gloo Mesh Gateway features that rely on Istio ServiceEntries.
      • If you have multiple external services that use the same host and plan to use Istio 1.20, 1.21, or 1.22, you must use patch versions 1.20.7, 1.21.3, or 1.22.0 or later to ensure that the Istio service entry that is created for those external services is correct.
      • The WasmDeploymentPolicy Gloo CR is currently unsupported in Istio versions 1.18 and later.