Merge "XenAPI: Refactor rotate_xen_guest_logs to avoid races"

tools/xenserver/rotate_xen_guest_logs.sh

@@ -18,48 +18,32 @@ log_dir="/var/log/xen/guest"
 kb=1024
 max_size_bytes=$(($kb*$kb))
 truncated_size_bytes=$((5*$kb))
-list_domains=/opt/xensource/bin/list_domains
 
 log_file_base="${log_dir}/console."
-tmp_file_base="${log_dir}/tmp.console."
 
 # Ensure logging is setup correctly for all domains
 xenstore-write /local/logconsole/@ "${log_file_base}%d"
 
-# Move logs we want to keep
-domains=$($list_domains | sed '/^id*/d' | sed 's/|.*|.*$//g' | xargs)
-for i in $domains; do
-    log="${log_file_base}$i"
-    tmp="${tmp_file_base}$i"
-    mv $log $tmp || true
+# Ensure the last_dom_id is set + updated for all running VMs
+for vm in $(xe vm-list power-state=running --minimal | tr ',' ' '); do
+    xe vm-param-set uuid=$vm other-config:last_dom_id=$(xe vm-param-get uuid=$vm param-name=dom-id)
 done
 
-# Delete all console logs,
-# mostly to remove logs from recently killed domains
-rm -f ${log_dir}/console.*
+# Get the last_dom_id for all VMs
+valid_last_dom_ids=$(xe vm-list params=other-config --minimal | tr ';,' '\n\n' | grep last_dom_id | sed -e 's/last_dom_id: //g' | xargs)
 
-# Reload domain list, in case it changed
-# (note we may have just deleted a new console log)
-domains=$($list_domains | sed '/^id*/d' | sed 's/|.*|.*$//g' | xargs)
-for i in $domains; do
-    log="${log_file_base}$i"
-    tmp="${tmp_file_base}$i"
+# Remove console files that do not correspond to valid last_dom_id's
+allowed_consoles=".*console.\(${valid_last_dom_ids// /\\|}\)$"
+find $log_dir -type f -not -regex $allowed_consoles -delete
 
-    if [ -e "$tmp" ]; then
-        size=$(stat -c%s "$tmp")
-
-        # Trim the log if required
-        if [ "$size" -gt "$max_size_bytes" ]; then
-            tail -c $truncated_size_bytes $tmp > $log || true
-        else
-            mv $tmp $log || true
-        fi
-    fi
+# Truncate all remaining logs
+for log in `find $log_dir -type f -regex '.*console.*' -size +${max_size_bytes}c`; do
+    tmp="$log.tmp"
+    tail -c $truncated_size_bytes $log > $tmp
+    mv -f $tmp $log
 
     # Notify xen that it needs to reload the file
-    xenstore-write /local/logconsole/$i $log
-    xenstore-rm /local/logconsole/$i
+    domid=${log##*.}
+    xenstore-write /local/logconsole/$domid $log
+    xenstore-rm /local/logconsole/$domid
 done
-
-# Delete all the tmp files
-rm -f ${tmp_file_base}* || true