osd: in cephx key init, don't overwrite key on failure

Previously, if the OSD cephx-keyring-update init container couldn't
contact the mons, the output redirect would overwrite the on-disk
keyring file with no text, removing the on-disk keyring.

Modify the init container to only overwrite the keyring file when the
ceph command to get the latest key suceeds, to avoid removing the
on-disk key.

Signed-off-by: Blaine Gardner <blaine.gardner@ibm.com>
(cherry picked from commit d69ffdfd2c)

pkg/operator/ceph/cluster/osd/spec.go

@@ -1492,11 +1492,16 @@ set -o xtrace
 OSD_ID="` + osdID + `"
 KEYRING_FILE=/var/lib/ceph/osd/ceph-"${OSD_ID}"/keyring
 
+# If this fails, it still writes to redirected file, so use temp file
 if ! ceph --name client.admin auth get-or-create osd."${OSD_ID}" \
 		mon 'allow profile osd' mgr 'allow profile osd' osd 'allow *' \
-		--keyring /etc/ceph/admin-keyring-store/keyring > "$KEYRING_FILE"; then
+		--keyring /etc/ceph/admin-keyring-store/keyring > /tmp/keyring; then
 	echo "failed to get latest cephx key for OSD. continuing OSD startup using on-disk key" >/dev/stderr
+	exit 0
 fi
+
+echo "got latest cephx key for OSD successfully. updating on-disk key" >/dev/stderr
+mv /tmp/keyring "$KEYRING_FILE"
 `
 	// ^ (above) Continue on failure here. Getting latest key can fail due to system issues that
 	// blocking here could make worse. Key rotation is rare, so on-disk key is likely good. If not,