@@ -8,7 +8,7 @@ jobs:
     # 'machine' executor runs Unit tests ~x1.5 faster, comparing to 'docker' executor
     # but the fastest is still ~x1.5-2 slower, comparing to Travis
     machine: true
-    parallelism: 2
+    parallelism: 3
     working_directory: ~/st2
     steps:
       - checkout
@@ -107,33 +107,48 @@ jobs:
 
   # Build & Test st2 packages
   packages:
-    parallelism: 2
+    parallelism: 3
     # 4CPUs & 8GB RAM CircleCI machine
     # sadly, it doesn't work with 'setup_remote_docker'
     resource_class: large
     docker:
       # The primary container is an instance of the first list image listed. Your build commands run in this container.
-      - image: circleci/python:3.6
+      - image: circleci/python:3.8
     working_directory: ~/st2
     environment:
-      - DISTROS: "focal el8"
+      - DISTROS: "focal el8 el9"
       - ST2_PACKAGES_REPO: https://github.com/StackStorm/st2-packages
       - ST2_PACKAGES: "st2"
       - ST2_CHECKOUT: 0
       - ST2_GITDIR: /tmp/st2
       - BASH_ENV: ~/.buildenv
     steps:
       - checkout
+      - run:
+          name: Install latest Docker Compose V2
+          command: |
+            set -x
+            export CODENAME=$(source /etc/os-release && echo "$VERSION_CODENAME")
+            export DISTRO=$(source /etc/os-release && echo "$ID")
+            export ARCH=$(dpkg --print-architecture)
+            # get gpg key for download.docker
+            curl -fsSL https://download.docker.com/linux/${DISTRO}/gpg | sudo gpg --dearmor -o /etc/apt/trusted.gpg.d/download.docker.gpg
+            # set source list
+            sudo tee <<<"deb [arch=${ARCH}] https://download.docker.com/linux/${DISTRO} ${CODENAME} stable" /etc/apt/sources.list.d/download.docker.list
+            # update package list
+            sudo apt update
+            # install docker CLI and Docker Compose v2
+            sudo apt install docker-ce-cli docker-compose-plugin
       - setup_remote_docker:
           reusable: true    # default - false
           exclusive: true   # default - true
-          version: 19.03.14
+          version: docker24
       - run:
           name: Docker version
           command: |
             set -x
             docker --version
-            docker-compose --version
+            docker compose version
       - run:
           name: Download st2-packages repository
           command: |
@@ -222,7 +237,7 @@ jobs:
       - image: circleci/ruby:2.7
     working_directory: /tmp/deploy
     environment:
-      - DISTROS: "focal el8"
+      - DISTROS: "focal el8 el9"
     steps:
       - attach_workspace:
           at: .
 
@@ -21,6 +21,8 @@ Added
   to pants' use of PEX lockfiles. This is not a user-facing addition.
   #6118 #6141 #6133
   Contributed by @cognifloyd
+* Build of ST2 EL9 packages #6153
+  Contributed by @amanda11
 
 3.8.1 - December 13, 2023
 -------------------------