Attempt to fix the gid collision

Author: pgnickb

ansible/tasks/setup-postgres.yml

@@ -292,6 +292,26 @@
     state: 'directory'
   become: true
 
+# Pin the systemd-coredump group/user before installing the package: its
+# postinst creates them with a dynamically-assigned system gid/uid (whatever
+# is next free at that point), which is not reproducible across AMI variants
+# that install a different set of packages before this point - it has
+# collided with the vector group's own pinned gid (989) on some builds.
+- name: add systemd-coredump system group
+  ansible.builtin.group:
+    name: systemd-coredump
+    gid: 986
+    system: yes
+
+- name: add systemd-coredump system user
+  ansible.builtin.user:
+    name: systemd-coredump
+    uid: 986
+    group: systemd-coredump
+    system: yes
+    create_home: false
+    shell: /usr/sbin/nologin
+
 # Required for this (plus CoredumpFilter= in postgresql.service and the
 # storage limits below) to do anything at all: without systemd-coredump,
 # core_pattern stays at the kernel's plain "core" default and none of this