images: Create single metrics dir in entrypoint

The entrypoint script for the Armada Docker container attempts to create
a nested, temporary directory when one is not provided through an
environment variable. This is fine when deploying Armada via a Helm
chart, as a writable volume mount exists; however, the directory
/tmp/armada/metrics does not exist when running as a standalone
container. This commit changes the entrypoint script to use a flat,
temporary directory to avoid requiring a user to mount a temporary
volume.

Change-Id: I26857908fa90c64c98038d508263a5094b06668a
Signed-off-by: Drew Walters <andrew.walters@att.com>

charts/armada/templates/deployment-api.yaml

@@ -138,8 +138,6 @@ spec:
           volumeMounts:
             - name: pod-tmp
               mountPath: /tmp
-            - name: pod-tmp-metrics
-              mountPath: /tmp/armada/metrics
             - name: pod-etc-armada
               mountPath: /etc/armada
             - name: armada-etc
@@ -195,9 +193,6 @@ spec:
       volumes:
         - name: pod-tmp
           emptyDir: {}
-        - name: pod-tmp-metrics
-          emptyDir:
-            medium: Memory
         - name: pod-etc-armada
           emptyDir: {}
         - name: armada-bin

entrypoint.sh

@@ -27,7 +27,7 @@ ARMADA_UWSGI_WORKERS=${ARMADA_UWSGI_WORKERS:-4}
 # Threads per worker
 ARMADA_UWSGI_THREADS=${ARMADA_UWSGI_THREADS:-1}
 # Prometheus multiprocess dir
-ARMADA_PROMETHEUS_MULTIPROC_DIR=${ARMADA_PROMETHEUS_MULTIPROC_DIR:-$(mktemp -d -p /tmp/armada/metrics XXXXXX)}
+ARMADA_PROMETHEUS_MULTIPROC_DIR=${ARMADA_PROMETHEUS_MULTIPROC_DIR:-$(mktemp -d -p /tmp armada-metrics-XXXXXX)}
 
 # Start Armada application
 # TODO(fmontei): Should be specifying callable too. But Armada spins up the