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.

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.

  • Envoy filter changes: The naming convention for EnvoyFilters changed. In addition, the functionality of the EXPERIMENTAL_SEGMENT_ENVOY_FILTERS_BY_MATCHER was promoted to standard behavior. The Gloo management server must re-create existing EnvoyFilters, which requires a careful upgrade procedure to avoid disruptions in your environment and policies from failing open.
  • Default add-ons namespace removed: The default gloo-mesh-addons namespace was removed and must now be manually set in the Helm chart. If omitted, add-ons are automatically deployed to the namespace that Gloo Mesh Gateway is installed to, which can lead to disruptions and downtime for your add-on components.

🔔 Medium

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

  • Prometheus annotations removed: The prometheus.io/port: "<port_number>" annotation was removed from the Gloo management server and agent in 2.5.0. However, the prometheus.io/scrape: true annotation is still present. When you use your own Prometheus instance to scrape metrics, the instance might try to scrape metrics from port numbers that require TLS authentication. This can lead to error messages in the logs. Note that this issue is resolved in 2.5.2.
  • Gloo UI auth secret: If you set up external authentication for the Gloo UI and you use the glooUi.auth.oidc.clientSecret Helm setting to reference the Kubernetes secret that stores your credentials, the secret might get deleted during the upgrade. To resolve issues after the upgrade, you must manually re-create the secret without any Helm labels or annotations. Note that this issue is resolved in version 2.5.8.

ℹī¸ Low

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

  • Known Portal issues in 2.5.2: A known issue exists in 2.5.2 that causes interruption during translation. This issue is resolved in version 2.5.3.
  • Upstream Prometheus 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 Helm pre-upgrade hooks to re-create the deployment, which can cause issues in automated environments such as Argo CD.

Envoy filter changes

The following Envoy filter changes were introduced in version 2.5.0. Both changes require the Envoy filters in your environment to be re-created.

  • New naming convention for Envoy filters:
    The naming convention for Envoy filters changed to ensure stable and consistent behavior during upgrades and policy changes. Before, the workload labels and a generated ID were used to build the Envoy filter name. Starting in 2.5.0, the name is built by using a combination of the Envoy filter namespace, cluster, workload labels, and a hash for the Envoy filter matchers. Note that Envoy filter names can still change if you update your workload selectors.

    To safely apply this change, make sure to carefully follow the Upgrade steps.

  • Break up large Envoy filters promoted to standard behavior:
    Some Gloo policies, such as JWT or other external auth policies are translated into Envoy filters during the Gloo translation process. These Envoy filters are created per proxy and are then applied to the ingress gateway or sidecar proxy to enforce the policies. In environments where you apply policies to a lot of apps and routes, the size of the Envoy filter can become very large and exceed the maximum file size limit in etcd. When the maximum file size limit is reached, new configuration is rejected in etcd and Istio, which leads to policies not being applied and enforced properly.

    To prevent this issue, the experimental environment variable EXPERIMENTAL_SEGMENT_ENVOY_FILTERS_BY_MATCHER was introduced in Gloo Mesh Gateway version 2.3 and 2.4. If enabled on the Gloo management server, the server automatically breaks up large Envoy filters and creates an Envoy filter per matcher. If the environment variable is not set, Envoy filters are created per proxy.

    Starting in version 2.5.0, the experimental environment variable is removed and its functionality is promoted to standard behavior. The Gloo management server now automatically creates Envoy filters for each matcher. If you did not previously enable the EXPERIMENTAL_SEGMENT_ENVOY_FILTERS_BY_MATCHER environment variable to create Envoy filters per matcher, your Envoy filters must be re-created as part of the upgrade to version 2.5.0.

Follow the Upgrade steps to safely upgrade your environment and re-create Envoy filters.

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 Gateway 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.

Gloo UI auth secret

If you set up external authentication for the Gloo UI and you use the glooUi.auth.oidc.clientSecret Helm setting to reference the Kubernetes secret that stores your credentials, the secret might get deleted during the upgrade. To resolve this issue after the upgrade, you must manually re-create the secret without any Helm labels or annotations.

Note that this issue is resolved in version 2.5.8.

Known Portal issues in 2.5.2

Gloo Mesh Gateway version 2.5.2 has a known issue in Portal that causes interruption during translation. This issue is resolved in version 2.5.3. Portal users are advised to skip version 2.5.2, and to directly upgrade to 2.5.3 instead.

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.

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.

⚒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 2.5.

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.

Failover priority

You can use the new priorityLabels field in the FailoverPolicy to prioritize destinations that get traffic in case of failure. Previously, you could only use localityMappings to set up basic failover from one location to another, not a prioritized order of multiple locations. For more information, see the Failover guide.

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 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 Gateway 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 Gateway 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

🚧 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.

  • GraphQL: For known issues regarding the GraphQL module, see the GraphQL documentation.

  • 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.
    • Istio 1.21 is not supported in Gloo Mesh Gateway version 2.5.
    • 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, you must use patch version 1.20.7 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.
      • 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.

    • Istio and Cilium: When you run Gloo Network with a supported CNI (Cilium or Calico), and a Gloo agent is deployed on a cluster with Istio CRDs, Gloo Mesh Gateway translates Istio resources to that cluster. This can affect existing Istio resources, such as gateways, that you do not want to be managed by Gloo Mesh Gateway.

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

    • Portal:

      • Gloo Mesh Gateway version 2.5.2 has a known issue in Portal that causes interruption during translation. This issue is resolved in version 2.5.3. Portal users are advised to skip version 2.5.2, and to directly upgrade to 2.5.3 instead.
      • For other known issues regarding the developer portal, see the Portal documentation.