Re: [kvm-unit-tests PATCH v3 4/8] migration: Support multiple migrations

Thomas Huth
2024-02-09T08:19:11Z

On 09/02/2024 08.01, Nicholas Piggin wrote:
> Support multiple migrations by flipping dest file/socket variables to
> source after the migration is complete, ready to start again. A new
> destination is created if the test outputs the migrate line again.
> Test cases may now switch to calling migrate() one or more times.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
...
> diff --git a/scripts/arch-run.bash b/scripts/arch-run.bash
> index 3689d7c2..a914ba17 100644
> --- a/scripts/arch-run.bash
> +++ b/scripts/arch-run.bash
> @@ -129,12 +129,16 @@ run_migration ()
> return 77
> fi
>
> + migcmdline=$@
> +
> trap 'trap - TERM ; kill 0 ; exit 2' INT TERM
> - trap 'rm -f ${migout1} ${migout_fifo1} ${migsock} ${qmp1} ${qmp2} ${fifo}' RETURN EXIT
> + trap 'rm -f ${migout1} ${migout2} ${migout_fifo1} ${migout_fifo2} ${migsock} ${qmp1} ${qmp2} ${fifo}' RETURN EXIT
>
> migsock=$(mktemp -u -t mig-helper-socket.XXXXXXXXXX)
> migout1=$(mktemp -t mig-helper-stdout1.XXXXXXXXXX)
> migout_fifo1=$(mktemp -u -t mig-helper-fifo-stdout1.XXXXXXXXXX)
> + migout2=$(mktemp -t mig-helper-stdout2.XXXXXXXXXX)
> + migout_fifo2=$(mktemp -u -t mig-helper-fifo-stdout2.XXXXXXXXXX)
> qmp1=$(mktemp -u -t mig-helper-qmp1.XXXXXXXXXX)
> qmp2=$(mktemp -u -t mig-helper-qmp2.XXXXXXXXXX)
> fifo=$(mktemp -u -t mig-helper-fifo.XXXXXXXXXX)
> @@ -142,18 +146,61 @@ run_migration ()
> qmpout2=/dev/null
>
> mkfifo ${migout_fifo1}
> - eval "$@" -chardev socket,id=mon1,path=${qmp1},server=on,wait=off \
> + mkfifo ${migout_fifo2}
> +
> + eval "$migcmdline" \
> + -chardev socket,id=mon1,path=${qmp1},server=on,wait=off \
> -mon chardev=mon1,mode=control > ${migout_fifo1} &
> live_pid=$!
> cat ${migout_fifo1} | tee ${migout1} &
>
> - # We have to use cat to open the named FIFO, because named FIFO's, unlike
> - # pipes, will block on open() until the other end is also opened, and that
> - # totally breaks QEMU...
> + # The test must prompt the user to migrate, so wait for the "migrate"
> + # keyword
> + while ! grep -q -i "Now migrate the VM" < ${migout1} ; do
> + if ! ps -p ${live_pid} > /dev/null ; then
> + echo "ERROR: Test exit before migration point." >&2
> + qmp ${qmp1} '"quit"'> ${qmpout1} 2>/dev/null
> + return 3
> + fi
> + sleep 0.1
> + done
> +
> + # This starts the first source QEMU in advance of the test reaching the
> + # migration point, since we expect at least one migration. Subsequent
> + # sources are started as the test hits migrate keywords.
> + do_migration || return $?
> +
> + while ps -p ${live_pid} > /dev/null ; do
> + # Wait for EXIT or further migrations
> + if ! grep -q -i "Now migrate the VM" < ${migout1} ; then
> + sleep 0.1
> + else
> + do_migration || return $?
> + fi
> + done
> +
> + wait ${live_pid}
> + ret=$?
> +
> + while (( $(jobs -r | wc -l) > 0 )); do
> + sleep 0.1
> + done
> +
> + return $ret
> +}
> +
> +do_migration ()
> +{
> + # We have to use cat to open the named FIFO, because named FIFO's,
> + # unlike pipes, will block on open() until the other end is also
> + # opened, and that totally breaks QEMU...
> mkfifo ${fifo}
> - eval "$@" -chardev socket,id=mon2,path=${qmp2},server=on,wait=off \
> - -mon chardev=mon2,mode=control -incoming unix:${migsock} < <(cat ${fifo}) &
> + eval "$migcmdline" \
> + -chardev socket,id=mon2,path=${qmp2},server=on,wait=off \
> + -mon chardev=mon2,mode=control -incoming unix:${migsock} \
> + < <(cat ${fifo}) > ${migout_fifo2} &
> incoming_pid=$!
> + cat ${migout_fifo2} | tee ${migout2} &
>
> # The test must prompt the user to migrate, so wait for the "migrate" keyword
> while ! grep -q -i "Now migrate the VM" < ${migout1} ; do

So the old check for the "migrate" keyword is also still around? Why do we
need to wait on two spots for the "Now mirgrate..." string now?

Thomas

> @@ -164,7 +211,7 @@ run_migration ()
> qmp ${qmp2} '"quit"'> ${qmpout2} 2>/dev/null
> return 3
> fi
> - sleep 1
> + sleep 0.1
> done
>
> # Wait until the destination has created the incoming and qmp sockets
> @@ -176,7 +223,7 @@ run_migration ()
> # Wait for the migration to complete
> migstatus=`qmp ${qmp1} '"query-migrate"' | grep return`
> while ! grep -q '"completed"' <<<"$migstatus" ; do
> - sleep 1
> + sleep 0.1
> if ! migstatus=`qmp ${qmp1} '"query-migrate"'`; then
> echo "ERROR: Querying migration state failed." >&2
> echo > ${fifo}
> @@ -192,14 +239,34 @@ run_migration ()
> return 2
> fi
> done
> +
> qmp ${qmp1} '"quit"'> ${qmpout1} 2>/dev/null
> +
> + # keypress to dst so getchar completes and test continues
> echo > ${fifo}
> - wait $incoming_pid
> + rm ${fifo}
> +
> + # Ensure the incoming socket is removed, ready for next destination
> + if [ -S ${migsock} ] ; then
> + echo "ERROR: Incoming migration socket not removed after migration." >& 2
> + qmp ${qmp2} '"quit"'> ${qmpout2} 2>/dev/null
> + return 2
> + fi
> +
> + wait ${live_pid}
> ret=$?
>
> - while (( $(jobs -r | wc -l) > 0 )); do
> - sleep 0.5
> - done
> + # Now flip the variables because dest becomes source
> + live_pid=${incoming_pid}
> + tmp=${migout1}
> + migout1=${migout2}
> + migout2=${tmp}
> + tmp=${migout_fifo1}
> + migout_fifo1=${migout_fifo2}
> + migout_fifo2=${tmp}
> + tmp=${qmp1}
> + qmp1=${qmp2}
> + qmp2=${tmp}
>
> return $ret
> }