Re: [Qemu-devel] [PATCH COLO-Frame v13 00/39] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service (FT)

[Hailiang Zhang <zhang.zhanghailiang@huawei.com>]

Cc: Markus Armbruster <armbru@redhat.com>

On 2015/12/29 15:08, zhanghailiang wrote:
> This is the 13th version of COLO (Still only support periodic checkpoint).
>
> Here is only COLO frame part, you can get the whole codes from github:
> https://github.com/coloft/qemu/commits/colo-v2.4-periodic-mode
>
> Please ignore patch 4 ~ 5 which have been picked by Dave into another series.
>
> 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. Checkpoint based on proxy in qemu
> 2. The capability of continuous FT
> 3. Optimize the VM's downtime during checkpoint
>
> v13:
>   - Refactor colo_*_cmd helper functions to use 'Error **errp' parameter
>    instead of return value to indicate success or failure. (patch 10)
>   - Remove the optional error message for COLO_EXIT event. (patch 25)
>   - Use semaphore to notify colo/colo incoming loop that failover work is
>     finished. (patch 26)
>   - Move COLO shutdown related codes to colo.c file. (patch 28)
>   - Fix memory leak bug for colo incoming loop. (new patch 31)
>   - Re-use some existed helper functions to realize the process of
>     saving/loading ram and device. (patch 32)
>   - Fix some other comments from Dave and Markus.
>
> 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 (39):
>    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 COLO_EXIT event to notify users while exited from COLO
>    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
>    savevm: Introduce two helper functions for save/find loadvm_handlers
>      entry
>    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           |  16 +
>   hmp-commands.hx               |  15 +
>   hmp.c                         |  15 +
>   hmp.h                         |   1 +
>   include/exec/ram_addr.h       |   9 +-
>   include/migration/colo.h      |  40 +++
>   include/migration/failover.h  |  33 ++
>   include/migration/migration.h |  21 +-
>   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              | 804 ++++++++++++++++++++++++++++++++++++++++++
>   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            | 248 +++++++++----
>   migration/tcp.c               |   4 +-
>   migration/unix.c              |   4 +-
>   net/filter-buffer.c           | 127 ++++++-
>   net/filter.c                  |   6 +-
>   net/net.c                     |  58 +++
>   qapi-schema.json              | 104 +++++-
>   qapi/event.json               |  15 +
>   qmp-commands.hx               |  24 +-
>   stubs/Makefile.objs           |   1 +
>   stubs/migration-colo.c        |  45 +++
>   trace-events                  |  10 +
>   vl.c                          |  30 +-
>   37 files changed, 2135 insertions(+), 197 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
>