Project: Contour (Orchestration & Management / Service Proxy)
File: CHANGELOG-v1.27.0.md

We are delighted to present version v1.27.0 of Contour, our layer 7 HTTP reverse proxy for Kubernetes clusters. A big thank you to everyone who contributed to the release. Envoy greedy matches routes and as a result the order route matches are presented to Envoy is important. Contour attempts to produce consistent routing tables so that the most specific route matches are given preference. This is done to facilitate consistency when using HTTPProxy inclusion and provide a uniform user experience for route matching to be inline with Ingress and Gateway API Conformance. This changes fixes the sorting algorithm used for `Prefix` and `Regex` based path matching. Previously the algorithm lexicographically sorted based on the path match string instead of sorting them based on the length of the `Prefix`|`Regex`. i.e. Longer prefix/regexes will be sorted first in order to give preference to more specific routes, then lexicographic sorting for things of the same length. Note that for prefix matching, this change is not expected to change the relative ordering of more specific prefixes vs. less specific ones when the more specific prefix match string has the less specific one as a prefix, e.g. `/foo/bar` will continue to sort before `/foo`. However, relative ordering of other combinations of prefix matches may change per the above description. Caution is advised if you update Contour and you are operating large routing tables. We advise you to: Deploy a duplicate Contour installation that parses the same CRDs Port-forward to the Envoy admin interface Access `http://127.0.0.1:9001/config_dump` and compare the configuration of Envoy. In particular the routes and their order. The prefix routes might be changing in order, so if they are you need to verify that the route matches as expected. (#5752, @davinci26) Setting `rateLimitPolicy.global.disabled` flag to true on a specific route now disables the global rate limit policy inherited from the virtual host for that route. In the example below, `/foo` route is opted out from the global rate limit policy defined by the virtualhost. ```yaml apiVersion: projectcontour.io/v1 kind: HTTPProxy metadata: name: echo spec: virtualhost: fqdn: local.projectcontour.io rateLimitPolicy: global: descriptors: entries: remoteAddress: {} genericKey: key: vhost value: local.projectcontour.io routes: conditions: prefix: / services: name: ingress-conformance-echo port: 80 conditions: prefix: /foo rateLimitPolicy: global: disabled: true services: name: ingress-conformance-echo port: 80 ``` (#5657, @shadialtarsha) Before this, we only waited for informer caches to sync but didn't wait for delivering the events to subscribed handlers. Now contour waits for the initial list of Kubernetes objects to be cached and processed by handlers (using the returned `HasSynced` methods) and then starts building its DAG and serving XDS. (#5672, @therealak12) This Change allows the host header to be rewritten on requests using dynamic headers on the only route level. ```yaml apiVersion: projectcontour.io/v1 kind: HTTPProxy metadata: name: dynamic-host-header-rewrite spec: fqdn:

routes: conditions: prefix: / services: name: s1 port: 80 requestHeaderPolicy: set: name: host value: "%REQ(x-rewrite-header)%" ``` (#5678, @clayton-gonsalves) This change optionally enables Contour to consume the kubernetes endpointslice API to determine the endpoints to configure Envoy with. Note: This change is off by default and is gated by the feature flag `useEndpointSlices`. This feature will be enabled by default in a future version on Contour once it has had sufficient bake time in production environments. (#5745, @clayton-gonsalves) Envoy v1.27.1 mitigates CVE-2023-44487 with some default runtime settings, however the `http.maxrequestsperiocycle` does not have a default value. This change allows configuring this runtime setting via Contour configuration to allow administrators of Contour to prevent abusive connections from starving resources from other valid connections. The default is left as the existing behavior (no limit) so as not to impact existing valid traffic. The Contour ConfigMap can be modified similar to the following (and Contour restarted) to set this value: ``` listener: max-requests-per-io-cycle: 10 ``` (Note this can be used in addition to the existing Listener configuration field `listener.max-requests-per-connection` which is used primarily for HTTP/1.1 connections and is an approximate limit for HTTP/2) See the for more details. (#5827, @sunjayBhatia) This field can be used to limit the number of concurrent streams Envoy will allow on a single connection from a downstream peer. It can be used to tune resource usage and as a mitigation for DOS attacks arising from vulnerabilities like CVE-2023-44487. The Contour ConfigMap can be modified similar to the following (and Contour restarted) to set this value: ``` listener: http2-max-concurrent-streams: 50 ``` (#5850, @sunjayBhatia) Add flags: `--incluster`, `--kubeconfig` for enable run the `gateway-provisioner` in or out of the cluster. (#5686, @izturn) Gateway provisioner: Add the `overloadMaxHeapSize` configuration option to contourDeployment to allow adding configuration when generating envoy's initial configuration file. (#5699, @yangyy93) Drops the Gateway API webhook from example manifests and testing since validations are now implemented in Common Expression Language (CEL). (#5735, @skriss) Gateway API: set Listeners' `ResolvedRefs` condition to `true` by default. (#5804, @skriss) Updates to Go 1.21.3. See the for more information. (#5841, @sunjayBhatia) Updates Envoy to v1.28.0. See the release notes . (#5870, @skriss) Switch to documenting the Gateway API release semantic version instead of API versions in versions.yaml and the , to provide more information about features available with each release. (#5871, @skriss) For a fresh install of Contour, consult the . To upgrade an existing Contour installation, please consult the . Contour v1.27.0 is tested against Kubernetes 1.26 through 1.28. Were immensely grateful for all the community contributions that help make Contour even better! For this release, special thanks go out to the following contributors: @clayton-gonsalves @davinci26 @izturn @shadialtarsha @therealak12 @yangyy93 If you're using Contour and want to add your organization to our adopters list, please visit this . If you prefer to keep your organization name anonymous but still give us feedback into your usage and scenarios for Contour, please post on this .