Introduction

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.

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.

Upstream Prometheus upgrade

Gloo Mesh Enterprise 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 Enterprise. The upgrade recreates the Prometheus server deployment at the new version.

Prometheus annotations removed

In Gloo version 2.5.0, the prometheus.io/port: "<port_number>" annotation was removed from the Gloo management server and agent. However, the prometheus.io/scrape: true annotation is still present. If you have another Prometheus instance that runs in your cluster, and it is not set up with custom scraping jobs for the Gloo management server and agent, the instance automatically scrapes all ports on the management server and agent pods. This can lead to error messages in the management server and agent logs. Note that this issue is resolved in version 2.5.2. To resolve this issue in Gloo version 2.5.0 or 2.5.1, see Run another Prometheus instance alongside the built-in one.

Default add-ons namespace removed

In previous releases, all add-ons were automatically installed to the gloo-mesh-addons namespace unless you specified a different namespace during the Gloo Gloo Mesh Enterprise installation. Starting with release 2.5.0, this default value is removed. If no value is set in the common.addonNamespace Helm field, your add-ons are now deployed to the namespace that the Helm release is installed to, which defaults to gloo-mesh. To avoid disruptions or downtime for your add-on components, such as a rate limit server, set the namespace you want your add-ons to be installed to in the common.addonNamespace field of your Helm values file.

Installation changes

In addition to comparing differences across versions in the changelog, review the following installation changes from the previous minor version to version 2.5.

Gloo agent health check port

Because you can now run the Gloo agent as a sidecar container in the management server pod, the default Gloo agent health check port is changed from 8090 to 8091.

Gloo UI

To use the Gloo UI and visualize the network traffic in your environment with the Gloo UI graph, you must set the telemetryCollector.enabled Helm setting to true in each cluster in your environment, including the management cluster.

Portal logs pipeline

The Gloo telemetry pipeline telemetryCollectorCustomization.pipelines.logs/istio_access_logs is renamed to telemetryCollectorCustomization.pipelines.logs/portal. For more information, see Monitor Portal analytics in the Gloo Mesh Gateway docs.

Bug fixes

Multiple Istio revisions in the same cluster

If you run multiple revisions of Istio in your cluster and use discoverySelectors in each revision to discover the resources in specific namespaces, enable the glooMgmtServer.extraEnvs.IGNORE_REVISIONS_FOR_VIRTUAL_DESTINATION_TRANSLATION environment variable on the Gloo management server. This setting allows virtual destinations to be translated correctly if the east-west gateway and the backing services belong to different namespaces.

To enable this feature, add the following values to your Helm values file.

  
glooMgmtServer:
  extraEnvs:
  - name: IGNORE_REVISIONS_FOR_VIRTUAL_DESTINATION_TRANSLATION
    value: "true"

To check if you use discoverySelectors in your Istio revision:

Istio lifecycle manager installations:

  1. Get the details of your Istio lifecycle manager resources.

      kubectl get istiolifecyclemanagers -A -o yaml

  2. In your Istio lifecycle manager resource, check if you use discoverySelectors in your spec.installations.istioOperatorSpec.meshConfig

      ...
spec:
 installations:
 - clusters:
   - defaultRevision: true
     name: mycluster
   istioOperatorSpec:
     components:
       pilot:
         k8s:
           env:
           - name: PILOT_SKIP_VALIDATE_TRUST_DOMAIN
             value: "true"
     meshConfig:
       discoverySelectors:
         - matchLabels:
             istio-discovery: enabled

Manual installations:

  1. Get the details of your Istio operator.

      kubectl get istiooperator -A -o yaml

  2. In your Istio operator configuration, check if you use discoverySelectors in your meshConfig settings.

      ...
meshConfig:
  discoverySelectors:
    - matchLabels:
        istio-discovery: enabled

New features

Review the following new features that are introduced in version 2.5 and that you can enable in your environment.

Redis safe mode

In versions 2.5.3 and lower, a race condition was identified that can 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 can lead to partial translations on the Gloo management server which can result in Istio resources being temporarily deleted from the output snapshots that are sent to the Gloo agents. For more information about this failure scenario, see Redis and Gloo management server restart. To resolve this issue, a new safe mode feature was added that you can enable by setting glooMgmtServer.safeMode Helm chart option to true.

If safe mode is enabled, translation of input snapshots halts until the input snapshots of all registered Gloo agents are present in the Redis cache. This feature improves management plane stability during disaster scenarios and upgrades. For more information, see Safe mode. The safe mode feature is disabled by default.

Redis safe start window

With safe mode, the Gloo management server halts translation until the input snapshots of all workload clusters are present in the Redis cache. However, if clusters have connectivity issues, translation might be halted for a long time, even for healthy clusters. You might want translation to resume after a certain period of time, even if some input snapshots are missing in the Redis cache. To do so, you must use the glooMgmtServer.safeStartWindow field in your Gloo management server Helm values file to specify the time in seconds to halt translation. Note that this setting is ignored if glooMgmtServer.safeMode is set to true. The default value is 180 seconds. You can disable the wait time by setting this field to 0 (zero). For more information, see Option 2: Safe start window.

I/O threads for Redis in 2.5.6

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.

      
glooMgmtServer:
  safeMode: true
redis: 
  deployment: 
    ioThreads: 2
    resources: 
      requests: 
        cpu: 3
      limits: 
        cpu: 3

New feature gate for east-west routes in JWT policies

Now, you can use the applyToRoutes selector in JWT policies to select east-west service mesh routes.

Previously, you could only select ingress routes that were attached to a virtual gateway. The use of a virtual gateway for ingress routes required a Gloo Mesh Gateway license in addition to your Gloo Mesh Enterprise license. For a Mesh-only scenario, you previously had to use the applyToDestinations selector. This meant that the same JWT policy applied to the destinations no matter how traffic reached them.

Now in 2.5.4 and later, you can use applyToRoutes for east-west routes. This way, you have more flexibility in how a destination is protected. For example, you might have several external and internal routes that go to the same backing destination. To secure these routes with different JWT policies, you can use applyToRoutes instead of applyToDestinations.

To enable this feature:

  1. Check your existing JWT policies that use applyToRoutes selectors and note the routes that they apply to.
  2. Check your existing route tables with the routes that you previously noted. In particular, check the selected proxy that routes traffic in the virtualGateway and workloadSelectors fields.
  3. Determine whether JWT policies apply to east-west service mesh routes.
    • If a route table includes a workload selector, or if a route table omits both the virtual gateway and workload selector fields: The JWT policies apply to the east-west service mesh routes. This might conflict with other JWT policies that already select the backing destinations of these routes.
    • If the route tables do not include a workload selector (except in the case that the route table also does not include a virtual gateway): The JWT policies do not apply to the east-west service mesh routes.
  4. Decide how to address the potential impact of updating the behavior of the JWT policy applyToRoutes selector.
    • To prevent JWT policies from applying to east-west service mesh routes, choose from the following options:
      • Update your configuration. For example, you might use a different label to select routes. Or, you might make separate route tables with separate route labels for your ingress routes vs. east-west routes.
      • Leave the feature gate disabled by keeping your Gloo Helm release with the featureGates.EnableJWTPolicyEastWestRoute value set to false.
    • To start applying JWT policies to east-west service mesh routes: Enable the feature gate by upgrading your Gloo Helm release with the featureGates.EnableJWTPolicyEastWestRoute value set to false.

For more information, see the following resources:

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 Enterprise) on AWS Fargate. For more information, see the Amazon EKS issue.
    • 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 Core features that rely on Istio ServiceEntries.
      • The WasmDeploymentPolicy Gloo CR is currently unsupported in Istio versions 1.18 and later.
      • For FIPS-compliant Solo distributions of Istio 1.17.2 and 1.16.4, you must use the -patch1 versions of the latest Istio builds published by Solo, such as 1.17.2-patch1-solo-fips for Solo distribution of Istio 1.17. These patch versions fix a FIPS-related issue introduced in the upstream Envoy code. In 1.17.3 and later, FIPS compliance is available in the -fips tags of regular Solo distributions of Istio, such as 1.17.3-solo-fips.