start-vnc: make killing vncserver optional

start-vnc

@@ -111,33 +111,40 @@ readonly SVNC_FRONTEND_HOST="mistral.dkrz.de"
 #
 # If your vncviewer client has trouble with TurboVNC's password format
 # then disable this option (set to "false" or comment).
-readonly SVNC_PASSWORD="true"
+readonly SVNC_PASSWORD=true
+
+# Kill vncserver job running if script ends for some reason
+readonly SVNC_KILLSERVER=true
 
 
 clean_up () {
     trap - ERR EXIT
     set +e
 
-    if [[ -n ${vnc_host:-} ]]; then
-        echo "Killing vncserver :${vnc_display} on ${vnc_host}."
-        ssh_frontend "ssh ${vnc_host} \"/opt/TurboVNC/bin/vncserver \
-                     -kill :${vnc_display}\""
-    fi
-
-    if [[ -n ${job_id:-} ]]; then
-        echo "Removing job ${job_id}."
-        ssh_frontend "scancel -Q ${job_id}; sleep 1; \
-                     rm -f .startvnc/out.${job_id}"
+    if ${SVNC_KILLSERVER}; then
+        if [[ -n ${vnc_host:-} ]]; then
+            echo "Killing vncserver :${vnc_display} on ${vnc_host}."
+            ssh_frontend "ssh ${vnc_host} \"/opt/TurboVNC/bin/vncserver \
+                         -kill :${vnc_display}\""
+        fi
+
+        if [[ -n ${job_id:-} ]]; then
+            echo "Removing job ${job_id}."
+            ssh_frontend "scancel -Q ${job_id}; sleep 1; \
+                         rm -f .startvnc/out.${job_id}"
+        else
+            echo "Job ID not available. Make sure the vncjob is not running!"
+            ssh_frontend "squeue -u ${SVNC_USERNAME}"
+        fi
     else
-        echo "Job ID not available. Make sure the vncjob is not running!"
-        ssh_frontend "squeue -u ${SVNC_USERNAME}"
+        echo "Kept job ${job_id} running."
     fi
 
     ssh_frontend "" "-O exit"
     rmdir "${ssh_socket_dir}"
 
     # Remove local vnc PasswordFile
-    if [[ ${SVNC_PASSWORD} = "true" ]]; then
+    if ${SVNC_PASSWORD}; then
         rm -f "vnc_passwd"
     fi
     exit
@@ -288,21 +295,21 @@ main () {
     echo "Vncserver started on node ${vnc_host}.dkrz.de display \
 :${vnc_display}."
 
-    local vnc_port_local=$((5900 + RANDOM % 100))
     # WSL doesn't seem to detect used ports so randomize
     # local port to reduce risk of masking.
+    local vnc_port_local=$((5900 + RANDOM % 100))
     local vnc_port_remote=$(( 5900 + vnc_display ))
-    while ! ssh -o ForwardX11=no \
-            -o StrictHostKeyChecking=accept-new \
-            -L "${vnc_port_local}:localhost:${vnc_port_remote}" \
-            -Nf \
-            "${SVNC_USERNAME}@${vnc_host}.dkrz.de"; do
+    until ssh -o ForwardX11=no \
+              -o StrictHostKeyChecking=accept-new \
+              -L "${vnc_port_local}:localhost:${vnc_port_remote}" \
+              -Nf \
+              "${SVNC_USERNAME}@${vnc_host}.dkrz.de"; do
         vnc_port_local=$((5900 + RANDOM % 100))
         echo "Trying local port ${vnc_port_local}."
     done
     local client_options
     client_options="${SVNC_CLIENT_OPTIONS:-}"
-    if [[ ${SVNC_PASSWORD} = "true" ]]; then
+    if ${SVNC_PASSWORD}; then
         echo "Fetching password from frontend."
         ssh_frontend "cat .vnc/passwd" > vnc_passwd
         client_options+=" -passwd vnc_passwd"