[JENKINS-73703] Remove UBI 8

With the upcoming EOL of Java 11, the UBI 8 image for Jenkins server
will no longer be supported. Creating a UBI 8 image therefore does not
make any sense.

Signed-off-by: Adam Kaplan <adam.kaplan@redhat.com>

README_agent.md

@@ -99,11 +99,6 @@ The image has several supported configurations, which can be accessed via the fo
       * `jenkins/agent:archlinux-jdk11`
       * `jenkins/agent:latest-archlinux`
       * `jenkins/agent:latest-archlinux-jdk11`
-    * rhel-ubi8 (Based on Red Hat Universal Base Image 8)
-      * `jenkins/agent:rhel-ubi8`
-      * `jenkins/agent:rhel-ubi8-jdk11`
-      * `jenkins/agent:latest-rhel-ubi8`
-      * `jenkins/agent:latest-rhel-ubi8-jdk11`
 
 * Windows Images:
   * Java 17 (default):

docker-bake.hcl

@@ -151,13 +151,6 @@ function "debian_platforms" {
   : ["linux/amd64", "linux/arm64", "linux/ppc64le", "linux/s390x"]))
 }
 
-# Return an array of RHEL UBI 8 platforms to use depending on the jdk passed as parameter
-# Note: Jenkins Docker controller only supports jdk-11 for ubi8
-function "rhel_ubi8_platforms" {
-  params = [jdk]
-  result = ["linux/amd64", "linux/arm64"]
-}
-
 # Return an array of RHEL UBI 8 platforms to use depending on the jdk passed as parameter
 # Note: Jenkins Docker controller only supports jdk-17 and jdk-21 for ubi9
 function "rhel_ubi9_platforms" {
@@ -248,33 +241,6 @@ target "agent_archlinux_jdk11" {
   platforms = ["linux/amd64"]
 }
 
-target "rhel_ubi8" {
-  matrix = {
-    type = ["agent", "inbound-agent"]
-    jdk  = [11]
-  }
-  name       = "${type}_rhel_ubi8_jdk${jdk}"
-  target     = type
-  dockerfile = "rhel/ubi8/Dockerfile"
-  context    = "."
-  args = {
-    VERSION        = REMOTING_VERSION
-    JAVA_VERSION   = "${javaversion(jdk)}"
-  }
-  tags = [
-    # If there is a tag, add versioned tag suffixed by the jdk
-    equal(ON_TAG, "true") ? "${REGISTRY}/${orgrepo(type)}:${REMOTING_VERSION}-${BUILD_NUMBER}-rhel-ubi8-jdk${jdk}" : "",
-    # If there is a tag and if the jdk is the default one, add versioned short tag
-    equal(ON_TAG, "true") ? (is_default_jdk(jdk) ? "${REGISTRY}/${orgrepo(type)}:${REMOTING_VERSION}-${BUILD_NUMBER}-rhel-ubi8" : "") : "",
-    # If the jdk is the default one, add rhel and latest short tags
-    is_default_jdk(jdk) ? "${REGISTRY}/${orgrepo(type)}:rhel-ubi8" : "",
-    is_default_jdk(jdk) ? "${REGISTRY}/${orgrepo(type)}:latest-rhel-ubi8" : "",
-    "${REGISTRY}/${orgrepo(type)}:rhel-ubi8-jdk${jdk}",
-    "${REGISTRY}/${orgrepo(type)}:latest-rhel-ubi8-jdk${jdk}",
-  ]
-  platforms = rhel_ubi8_platforms(jdk)
-}
-
 target "rhel_ubi9" {
   matrix = {
     type = ["agent", "inbound-agent"]