test(nrdot): preemptively remove pre-installed containerd before docker-ce

Follow-up to eb0ea25. The 'allowerasing' flag alone doesn't unblock the
docker-ce install on newer RHEL 9 AMIs: the conflict is an RPM-level
'Conflicts:' declaration between RHEL AppStream's 'containerd' and
docker.com's 'containerd.io', which fails at dnf's transaction check
stage (before allowerasing gets a chance to resolve deps).

Preemptively remove any pre-installed 'containerd' / 'containerd.io'
packages (both dnf-remove and rpm -e --nodeps as a fallback) so the
subsequent docker-ce.repo install can bring in its own containerd.io
cleanly.

Applies to both nrdot RHEL 9 deploy scripts (kafka, rabbitmq).

Author: pranav-new-relic

test/deploy/linux/nrdot-kafka/install/rhel/roles/configure/tasks/main.yml

@@ -14,6 +14,20 @@
     args:
       creates: /etc/yum.repos.d/docker-ce.repo
 
+  # Newer RHEL 9 AMIs ship containerd.io pre-installed from the AppStream
+  # repo. When we later add docker-ce.repo and try to install docker-ce,
+  # dnf's transitive resolver pulls RHEL's `containerd` package (from
+  # AppStream), which has an RPM-level Conflicts: against the pre-installed
+  # `containerd.io`. The transaction check then fails even with
+  # allowerasing=true, because it's an RPM conflict, not a dep-resolution
+  # ambiguity. Preemptively remove any pre-installed containerd* so
+  # docker-ce.repo's containerd.io can install cleanly.
+  - name: remove any pre-installed containerd packages (avoid docker-ce install conflict)
+    shell: |
+      dnf remove -y containerd containerd.io 2>/dev/null || true
+      rpm -e --nodeps containerd containerd.io 2>/dev/null || true
+      true
+
   - name: install Docker CE with compose and buildx plugins
     dnf:
       name:
@@ -23,11 +37,6 @@
         - docker-compose-plugin
         - docker-buildx-plugin
       state: present
-      # Newer RHEL 9 AMIs ship containerd.io pre-installed; without
-      # allowerasing, yum's transitive dep resolution tries to install
-      # RHEL's own 'containerd' package which conflicts with the pre-
-      # installed 'containerd.io' and the transaction fails.
-      allowerasing: yes
 
   - name: start and enable Docker
     systemd:

test/deploy/linux/nrdot-rabbitmq/install/rhel/roles/configure/tasks/main.yml

@@ -14,11 +14,15 @@
       else
         yum install -y yum-utils
         yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
-        # Newer RHEL 9 AMIs ship containerd.io pre-installed; without
-        # --allowerasing, dnf's transitive dep resolution tries to install
-        # RHEL's own 'containerd' package which conflicts with the pre-
-        # installed 'containerd.io' and the transaction fails.
-        yum install --allowerasing -y docker-ce docker-ce-cli containerd.io
+        # Newer RHEL 9 AMIs ship containerd.io pre-installed from AppStream.
+        # docker-ce install pulls RHEL's `containerd` as a transitive dep,
+        # which has an RPM-level Conflicts: with the pre-installed
+        # containerd.io — the check fails even with --allowerasing.
+        # Preemptively remove containerd* so docker-ce.repo's version can
+        # install cleanly.
+        dnf remove -y containerd containerd.io 2>/dev/null || true
+        rpm -e --nodeps containerd containerd.io 2>/dev/null || true
+        yum install -y docker-ce docker-ce-cli containerd.io
         systemctl start docker
         systemctl enable docker
       fi