[libvirt] [PATCH v2] Init script for handling guests on shutdown/boot

[Eric Blake]

On 05/18/2010 07:27 AM, Jiri Denemark wrote:
> 
> Version 2 changes:
> - fixes suggested by Eric
> - configurable ON_BOOT and ON_SHUTDOWN behavior inspired by Gerd
> 
> +++ b/daemon/libvirt-guests.init.in
> @@ -0,0 +1,295 @@
> +
> +sysconfdir=@sysconfdir@
> +localstatedir=@localstatedir@

Just in case @sysconfdir@ has spaces (if it has ', the user's hosed
themselves anyway):

sysconfdir='@sysconfdir@'
localstatedir='@localstatedir@'

But libvirtd.init.in does the same, so at this point, any cleanups for
minor issues like that can be done across both scripts at once, as a
separate patch.

> +
> +stop() {
> +    # last stop was not followed by start
> +    [ -f $LISTFILE ] && return 0
> +
> +    suspending=true
> +    if [ "x$ON_SHUTDOWN" = xshutdown ]; then
> +        suspending=false
> +        if [ $SHUTDOWN_TIMEOUT -le 0 ]; then
> +            echo $"Shutdown action requested but SHUTDOWN_TIMEOUT was not set"
> +            RETVAL=6
> +            return
> +        fi
> +    fi
> +
> +    : >$LISTFILE
> +    for uri in $URIS; do
> +        echo -n $"Running guests on $uri URI: "
> +        list=$(list_guests $uri)
> +        if [ $? -eq 0 ]; then
> +            empty=true
> +            for uuid in $list; do
> +                $empty || printf ", "
> +                echo -n $(guest_name $uri $uuid)
> +                empty=false
> +            done
> +            if $empty; then
> +                echo $"no running guests."
> +            else
> +                echo
> +                echo $uri $list >>$LISTFILE
> +            fi
> +        fi
> +    done
> +
> +    while read uri list; do
> +        if $suspending; then
> +            echo $"Suspending guests on $uri URI..."
> +        else
> +            echo $"Shutting down guests on $uri URI..."
> +        fi
> +
> +        for guest in $list; do
> +            if $suspending; then
> +                suspend_guest $uri $guest
> +            else
> +                shutdown_guest $uri $guest
> +            fi
> +        done
> +    done <$LISTFILE
> +}

This works as is, so need to change it.  But I would have done something
along these lines:

how=suspend_guest
if [ "x$ON_SHUTDOWN" = xshutdown ]; then
    how=shutdown_guest
fi
...
for guest in $list; do
    $how $uri $guest
done

to cut down on some of the logic.

> +    shutdown)
> +        ON_SHUTDOWN=shutdown
> +        stop
> +        ;;

If someone calls 'service libvirt-guests shutdown', but...

> +# action taken on host shutdown
> +# - suspend   all running guests are suspended using virsh managedsave
> +# - shutdown  all running guests are asked to shutdown. Please be careful with
> +#             this settings since there is no way to distinguish between a
> +#             guest which is stuck or ignores shutdown requests and a guest
> +#             which just needs a long time to shutdown. When setting
> +#             ON_SHUTDOWN=shutdown, you must also set SHUTDOWN_TIMEOUT to a
> +#             value suitable for your guests.
> +#ON_SHUTDOWN=suspend
> +
> +# number of seconds we're willing to wait for a guest to shut down
> +#SHUTDOWN_TIMEOUT=0

...left their config with the defaults, then the shutdown will fail
because SHUTDOWN_TIMEOUT is still 0.  I guess that makes sense, though.
 Are we sure that init scripts called during '/sbin/shutdown' are
normally called with 'stop' rather than 'shutdown' argument?

Looks nicer!  ACK.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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