Resolve "Egress Whitelist - Gitlab Runner"
General MR
Summary
This MR introduces a Sidecar and a set of ServiceEntries for Gitlab Runner when istio.enabled: true and istio.hardened.enabled: true. This is in support of big-bang&160.
Relevant logs/screenshots
Bigbang testing MR: big-bang/bigbang!4218 (closed)
Linked Issue
Upgrade Notices
A Sidecar resource has been added to the gitlab-runner namespace that disallows egress to endpoints that are not part of the Istio service registry (a.k.a REGISTRY_ONLY). The outboundTrafficPolicy.mode in the Sidecar can be configured, however, to be something other than REGISTRY_ONLY if desired by setting istio.hardened.outboundTrafficPolicyMode. This provides a redundant layer of network security in addition to NetworkPolicies. This Sidecar is disabled by default but can be enabled by setting istio.enabled: true and istio.hardened.enabled: true.
Additional custom ServiceEntries can be created by populating the istio.hardened.customServiceEntries list.