Re: [Qemu-devel] [PATCH COLO-Frame v12 00/38] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service (FT)

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Hailiang Zhang (zhang.zhanghailiang@huawei.com) wrote:
> On 2015/12/15 20:14, Dr. David Alan Gilbert wrote:
> >* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
> >>This is the 12th version of COLO.
> >>
> >>As usual, this version of COLO is only support periodic checkpoint,
> >>just like MicroCheckpointing and Remus does.
> >>
> >>Here is only COLO frame part, you can get the whole codes from github:
> >>https://github.com/coloft/qemu/commits/colo-v2.3-periodic-mode
> >
> >Hi,
> >   Have you tried wiring in Zhang Chen's new userland colo proxy yet?
> >I'd like to start trying it out.
> >
> 
> Not yet, actually, for frame part, we can re-use most of the previous codes that based on
> kernel proxy. And, yes, please, you are welcome to join us. ;)

Yes, that's certainly something I'll look at immediately at the start of the new year
(I'm out for 2 weeks from Friday).

I've just tested this series on my machines, and it works well.
Two things:
  1) I just posted a patch to add an HMP equivalent to x-blockdev-change
  2) If you run with an older machine type (e.g. pc-i440fx-2.3) then if I failover to the
secondary then I hit a 'invalid runstate transition: 'inmigrate' -> 'prelaunch'';
I guess this is something to do with global_state.

Dave

> >Dave
> >
> >>Test procedure:
> >>1. Startup qemu
> >>Primary side:
> >>#x86_64-softmmu/qemu-system-x86_64 -enable-kvm -boot c -m 2048 -smp 2 -qmp stdio -vnc :7 -name primary -cpu qemu64,+kvmclock -device piix3-usb-uhci -device usb-tablet -netdev tap,id=hn0,vhost=off -device virtio-net-pci,id=net-pci0,netdev=hn0 -drive if=virtio,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,children.0.file.filename=/mnt/sdd/pure_IMG/linux/redhat/rhel_6.5_64_2U_ide,children.0.driver=raw
> >>Secondary side:
> >>#x86_64-softmmu/qemu-system-x86_64 -boot c -m 2048 -smp 2 -qmp stdio -vnc :7 -name secondary -enable-kvm -cpu qemu64,+kvmclock -device piix3-usb-uhci -device usb-tablet -netdev tap,id=hn0,vhost=off -device virtio-net-pci,id=net-pci0,netdev=hn0 -drive if=none,id=colo-disk0,file.filename=/mnt/sdd/pure_IMG/linux/redhat/rhel_6.5_64_2U_ide,driver=raw,node-name=node0 -drive if=virtio,id=active-disk0,throttling.bps-total=70000000,driver=replication,mode=secondary,file.driver=qcow2,file.file.filename=/mnt/ramfs/active_disk.img,file.backing.driver=qcow2,file.backing.file.filename=/mnt/ramfs/hidden_disk.img,file.backing.backing=colo-disk0 -incoming tcp:0:8888
> >>2. On Secondary VM's QEMU monitor, issue command
> >>{'execute':'qmp_capabilities'}
> >>{'execute': 'nbd-server-start', 'arguments': {'addr': {'type': 'inet', 'data': {'host': '192.168.2.88', 'port': '8889'} } } }
> >>{'execute': 'nbd-server-add', 'arguments': {'device': 'colo-disk0', 'writable': true } }
> >>{'execute': 'trace-event-set-state', 'arguments': {'name': 'colo*', 'enable': true} }
> >>
> >>3. On Primary VM's QEMU monitor, issue command:
> >>{'execute':'qmp_capabilities'}
> >>{'execute': 'human-monitor-command', 'arguments': {'command-line': 'drive_add buddy driver=replication,mode=primary,file.driver=nbd,file.host=9.61.1.7,file.port=8889,file.export=colo-disk0,node-name=node0,if=none'}}
> >>{'execute':'x-blockdev-change', 'arguments':{'parent': 'colo-disk0', 'node': 'node0' } }
> >>{'execute': 'migrate-set-capabilities', 'arguments': {'capabilities': [ {'capability': 'x-colo', 'state': true } ] } }
> >>{'execute': 'migrate', 'arguments': {'uri': 'tcp:192.168.2.88:8888' } }
> >>
> >>4. After the above steps, you will see, whenever you make changes to PVM, SVM will be synced.
> >>You can by issue command '{ "execute": "migrate-set-parameters" , "arguments":{ "x-checkpoint-delay": 2000 } }'
> >>to change the checkpoint period time.
> >>
> >>5. Failover test
> >>You can kill Primary VM and run 'x_colo_lost_heartbeat' in Secondary VM's
> >>monitor at the same time, then SVM will failover and client will not feel this
> >>change.
> >>
> >>Before issuing '{ "execute": "x-colo-lost-heartbeat" }' command, we have to
> >>issue block related command to stop block replication.
> >>Primary:
> >>   Remove the nbd child from the quorum:
> >>   { 'execute': 'x-blockdev-change', 'arguments': {'parent': 'colo-disk0', 'child': 'children.1'}}
> >>   Note: there is no qmp command to remove the blockdev now
> >>
> >>Secondary:
> >>   The primary host is down, so we should do the following thing:
> >>   { 'execute': 'nbd-server-stop' }
> >>
> >>Please review, thanks.
> >>
> >>TODO:
> >>1. Implement packets compare module (proxy) in qemu (Doing)
> >>2. Checkpoint based on proxy in qemu
> >>3. The capability of continuous FT
> >>
> >>v12:
> >>  - Fix the bug that default buffer filter broken vhost-net.
> >>  - Add an flag in struct NetFilterState to help skipping default
> >>   filter for packets travelling through filter layer.
> >>  - Remove the default failover treatment which may cause split-brain.
> >>  - Rename checkpoint-delay to x-checkpoint-delay.
> >>  - Check if all netdev supports default filter before going into COLO.
> >>  - Reconstruct send/receive helper functions in patch 10.
> >>  - Address serveral other comments from Dave
> >>
> >>v11:
> >>  - Re-implement buffer/release packets based on filter-buffer according
> >>    to Jason Wang's suggestion. (patch 34, patch 36 ~ patch 38)
> >>  - Rebase master to re-use some stuff introduced by post-copy.
> >>  - Address several comments from Eric and Dave, the fixing record can
> >>    be found in each patch.
> >>
> >>v10:
> >>  - Rename 'colo_lost_heartbeat' command to experimental 'x_colo_lost_heartbeat'
> >>  - Rename migration capability 'colo' to 'x-colo' (Eric's suggestion)
> >>  - Simplify the process of primary side by dropping colo thread and reusing
> >>    migration thread. (Dave's suggestion)
> >>  - Add several netfilter related APIs to support buffer/release packets
> >>    for COLO (patch 32 ~ patch 36)
> >>
> >>zhanghailiang (38):
> >>   configure: Add parameter for configure to enable/disable COLO support
> >>   migration: Introduce capability 'x-colo' to migration
> >>   COLO: migrate colo related info to secondary node
> >>   migration: Export migrate_set_state()
> >>   migration: Add state records for migration incoming
> >>   migration: Integrate COLO checkpoint process into migration
> >>   migration: Integrate COLO checkpoint process into loadvm
> >>   migration: Rename the'file' member of MigrationState
> >>   COLO/migration: Create a new communication path from destination to
> >>     source
> >>   COLO: Implement colo checkpoint protocol
> >>   COLO: Add a new RunState RUN_STATE_COLO
> >>   QEMUSizedBuffer: Introduce two help functions for qsb
> >>   COLO: Save PVM state to secondary side when do checkpoint
> >>   ram: Split host_from_stream_offset() into two helper functions
> >>   COLO: Load PVM's dirty pages into SVM's RAM cache temporarily
> >>   ram/COLO: Record the dirty pages that SVM received
> >>   COLO: Load VMState into qsb before restore it
> >>   COLO: Flush PVM's cached RAM into SVM's memory
> >>   COLO: Add checkpoint-delay parameter for migrate-set-parameters
> >>   COLO: synchronize PVM's state to SVM periodically
> >>   COLO failover: Introduce a new command to trigger a failover
> >>   COLO failover: Introduce state to record failover process
> >>   COLO: Implement failover work for Primary VM
> >>   COLO: Implement failover work for Secondary VM
> >>   qmp event: Add event notification for COLO error
> >>   COLO failover: Shutdown related socket fd when do failover
> >>   COLO failover: Don't do failover during loading VM's state
> >>   COLO: Process shutdown command for VM in COLO state
> >>   COLO: Update the global runstate after going into colo state
> >>   savevm: Split load vm state function qemu_loadvm_state
> >>   COLO: Separate the process of saving/loading ram and device state
> >>   COLO: Split qemu_savevm_state_begin out of checkpoint process
> >>   net/filter-buffer: Add default filter-buffer for each netdev
> >>   filter-buffer: Accept zero interval
> >>   filter-buffer: Introduce a helper function to enable/disable default
> >>     filter
> >>   filter-buffer: Introduce a helper function to release packets
> >>   colo: Use default buffer-filter to buffer and release packets
> >>   COLO: Add block replication into colo process
> >>
> >>  configure                     |  11 +
> >>  docs/qmp-events.txt           |  17 +
> >>  hmp-commands.hx               |  15 +
> >>  hmp.c                         |  15 +
> >>  hmp.h                         |   1 +
> >>  include/exec/ram_addr.h       |   9 +-
> >>  include/migration/colo.h      |  38 +++
> >>  include/migration/failover.h  |  33 ++
> >>  include/migration/migration.h |  18 +-
> >>  include/migration/qemu-file.h |   3 +-
> >>  include/net/filter.h          |  12 +
> >>  include/net/net.h             |   5 +
> >>  include/sysemu/sysemu.h       |   9 +
> >>  migration/Makefile.objs       |   2 +
> >>  migration/colo-comm.c         |  71 ++++
> >>  migration/colo-failover.c     |  83 +++++
> >>  migration/colo.c              | 765 ++++++++++++++++++++++++++++++++++++++++++
> >>  migration/exec.c              |   4 +-
> >>  migration/fd.c                |   4 +-
> >>  migration/migration.c         | 216 ++++++++----
> >>  migration/postcopy-ram.c      |   6 +-
> >>  migration/qemu-file-buf.c     |  61 ++++
> >>  migration/ram.c               | 213 ++++++++++--
> >>  migration/rdma.c              |   2 +-
> >>  migration/savevm.c            | 295 ++++++++++++----
> >>  migration/tcp.c               |   4 +-
> >>  migration/unix.c              |   4 +-
> >>  net/filter-buffer.c           | 127 ++++++-
> >>  net/filter.c                  |   6 +-
> >>  net/net.c                     |  58 ++++
> >>  qapi-schema.json              | 106 +++++-
> >>  qapi/event.json               |  17 +
> >>  qmp-commands.hx               |  24 +-
> >>  stubs/Makefile.objs           |   1 +
> >>  stubs/migration-colo.c        |  45 +++
> >>  trace-events                  |  10 +
> >>  vl.c                          |  37 +-
> >>  37 files changed, 2152 insertions(+), 195 deletions(-)
> >>  create mode 100644 include/migration/colo.h
> >>  create mode 100644 include/migration/failover.h
> >>  create mode 100644 migration/colo-comm.c
> >>  create mode 100644 migration/colo-failover.c
> >>  create mode 100644 migration/colo.c
> >>  create mode 100644 stubs/migration-colo.c
> >>
> >>--
> >>1.8.3.1
> >>
> >>
> >--
> >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >
> >.
> >
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK