[baseimage]: specify gid for redis group. (#7249)

Problem:
Default groupadd for redis, takes 1000 by default. This forces, subsequently created admin group to get 1001.
As all TACACS users are created with 1000 as their gid, they end up in redis group.

Fix:
Create redis group *after* admin group is created
Add a check that admin group id is 1000

build_debian.sh

@@ -233,15 +233,16 @@ sudo cp files/docker/docker.service.conf $_
 ## Fix systemd race between docker and containerd
 sudo sed -i '/After=/s/$/ containerd.service/' $FILESYSTEM_ROOT/lib/systemd/system/docker.service
 
-## Create redis group
-sudo LANG=C chroot $FILESYSTEM_ROOT groupadd -f redis
-
 ## Create default user
 ## Note: user should be in the group with the same name, and also in sudo/docker/redis groups
-sudo LANG=C chroot $FILESYSTEM_ROOT useradd -G sudo,docker,redis $USERNAME -c "$DEFAULT_USERINFO" -m -s /bin/bash
+sudo LANG=C chroot $FILESYSTEM_ROOT useradd -G sudo,docker $USERNAME -c "$DEFAULT_USERINFO" -m -s /bin/bash
 ## Create password for the default user
 echo "$USERNAME:$PASSWORD" | sudo LANG=C chroot $FILESYSTEM_ROOT chpasswd
 
+## Create redis group
+sudo LANG=C chroot $FILESYSTEM_ROOT groupadd -f redis
+sudo LANG=C chroot $FILESYSTEM_ROOT usermod -aG redis $USERNAME
+
 if [[ $CONFIGURED_ARCH == amd64 ]]; then
     ## Pre-install hardware drivers
     sudo LANG=C chroot $FILESYSTEM_ROOT apt-get -y install      \
@@ -531,6 +532,13 @@ sudo du -hsx $FILESYSTEM_ROOT
 sudo mkdir -p $FILESYSTEM_ROOT/var/lib/docker
 sudo mksquashfs $FILESYSTEM_ROOT $FILESYSTEM_SQUASHFS -e boot -e var/lib/docker -e $PLATFORM_DIR
 
+
+# Ensure admin gid is 1000
+gid_user=$(sudo LANG=C chroot $FILESYSTEM_ROOT id -g $USERNAME) || gid_user="none"
+if [ "${gid_user}" != "1000" ]; then
+    die "expect gid 1000. current:${gid_user}"
+fi
+
 ## Compress docker files
 pushd $FILESYSTEM_ROOT && sudo tar czf $OLDPWD/$FILESYSTEM_DOCKERFS -C ${DOCKERFS_PATH}var/lib/docker .; popd