zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 1 | COarse-grained LOck-stepping Virtual Machines for Non-stop Service |
| 2 | ---------------------------------------- |
| 3 | Copyright (c) 2016 Intel Corporation |
| 4 | Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD. |
| 5 | Copyright (c) 2016 Fujitsu, Corp. |
| 6 | |
| 7 | This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 8 | See the COPYING file in the top-level directory. |
| 9 | |
| 10 | This document gives an overview of COLO's design and how to use it. |
| 11 | |
| 12 | == Background == |
| 13 | Virtual machine (VM) replication is a well known technique for providing |
| 14 | application-agnostic software-implemented hardware fault tolerance, |
| 15 | also known as "non-stop service". |
| 16 | |
| 17 | COLO (COarse-grained LOck-stepping) is a high availability solution. |
| 18 | Both primary VM (PVM) and secondary VM (SVM) run in parallel. They receive the |
| 19 | same request from client, and generate response in parallel too. |
| 20 | If the response packets from PVM and SVM are identical, they are released |
| 21 | immediately. Otherwise, a VM checkpoint (on demand) is conducted. |
| 22 | |
| 23 | == Architecture == |
| 24 | |
| 25 | The architecture of COLO is shown in the diagram below. |
| 26 | It consists of a pair of networked physical nodes: |
| 27 | The primary node running the PVM, and the secondary node running the SVM |
| 28 | to maintain a valid replica of the PVM. |
| 29 | PVM and SVM execute in parallel and generate output of response packets for |
| 30 | client requests according to the application semantics. |
| 31 | |
| 32 | The incoming packets from the client or external network are received by the |
| 33 | primary node, and then forwarded to the secondary node, so that both the PVM |
| 34 | and the SVM are stimulated with the same requests. |
| 35 | |
| 36 | COLO receives the outbound packets from both the PVM and SVM and compares them |
| 37 | before allowing the output to be sent to clients. |
| 38 | |
| 39 | The SVM is qualified as a valid replica of the PVM, as long as it generates |
| 40 | identical responses to all client requests. Once the differences in the outputs |
| 41 | are detected between the PVM and SVM, COLO withholds transmission of the |
| 42 | outbound packets until it has successfully synchronized the PVM state to the SVM. |
| 43 | |
Zhang Chen | a38299b | 2016-11-01 11:38:12 +0800 | [diff] [blame] | 44 | Primary Node Secondary Node |
| 45 | +------------+ +-----------------------+ +------------------------+ +------------+ |
| 46 | | | | HeartBeat +<----->+ HeartBeat | | | |
| 47 | | Primary VM | +-----------+-----------+ +-----------+------------+ |Secondary VM| |
| 48 | | | | | | | |
| 49 | | | +-----------|-----------+ +-----------|------------+ | | |
| 50 | | | |QEMU +---v----+ | |QEMU +----v---+ | | | |
| 51 | | | | |Failover| | | |Failover| | | | |
| 52 | | | | +--------+ | | +--------+ | | | |
| 53 | | | | +---------------+ | | +---------------+ | | | |
| 54 | | | | | VM Checkpoint +-------------->+ VM Checkpoint | | | | |
| 55 | | | | +---------------+ | | +---------------+ | | | |
| 56 | |Requests<--------------------------\ /-----------------\ /--------------------->Requests| |
| 57 | | | | ^ ^ | | | | | | | |
| 58 | |Responses+---------------------\ /-|-|------------\ /-------------------------+Responses| |
| 59 | | | | | | | | | | | | | | | | | |
| 60 | | | | +-----------+ | | | | | | | | | | +----------+ | | | |
| 61 | | | | | COLO disk | | | | | | | | | | | | COLO disk| | | | |
| 62 | | | | | Manager +---------------------------->| Manager | | | | |
| 63 | | | | ++----------+ v v | | | | | v v | +---------++ | | | |
| 64 | | | | |+-----------+-+-+-++| | ++-+--+-+---------+ | | | | |
| 65 | | | | || COLO Proxy || | | COLO Proxy | | | | | |
| 66 | | | | || (compare packet || | |(adjust sequence | | | | | |
| 67 | | | | ||and mirror packet)|| | | and ACK) | | | | | |
| 68 | | | | |+------------+---+-+| | +-----------------+ | | | | |
| 69 | +------------+ +-----------------------+ +------------------------+ +------------+ |
| 70 | +------------+ | | | | +------------+ |
| 71 | | VM Monitor | | | | | | VM Monitor | |
| 72 | +------------+ | | | | +------------+ |
| 73 | +---------------------------------------+ +----------------------------------------+ |
| 74 | | Kernel | | | | | Kernel | | |
| 75 | +---------------------------------------+ +----------------------------------------+ |
| 76 | | | | | |
| 77 | +--------------v+ +---------v---+--+ +------------------+ +v-------------+ |
| 78 | | Storage | |External Network| | External Network | | Storage | |
| 79 | +---------------+ +----------------+ +------------------+ +--------------+ |
| 80 | |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 81 | |
| 82 | == Components introduction == |
| 83 | |
| 84 | You can see there are several components in COLO's diagram of architecture. |
| 85 | Their functions are described below. |
| 86 | |
| 87 | HeartBeat: |
| 88 | Runs on both the primary and secondary nodes, to periodically check platform |
| 89 | availability. When the primary node suffers a hardware fail-stop failure, |
| 90 | the heartbeat stops responding, the secondary node will trigger a failover |
| 91 | as soon as it determines the absence. |
| 92 | |
| 93 | COLO disk Manager: |
zhaolichang | 76ca4b5 | 2020-09-17 15:50:22 +0800 | [diff] [blame] | 94 | When primary VM writes data into image, the colo disk manager captures this data |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 95 | and sends it to secondary VM's which makes sure the context of secondary VM's |
| 96 | image is consistent with the context of primary VM 's image. |
| 97 | For more details, please refer to docs/block-replication.txt. |
| 98 | |
| 99 | Checkpoint/Failover Controller: |
| 100 | Modifications of save/restore flow to realize continuous migration, |
| 101 | to make sure the state of VM in Secondary side is always consistent with VM in |
| 102 | Primary side. |
| 103 | |
| 104 | COLO Proxy: |
Like Xu | 806be37 | 2019-02-20 13:27:26 +0800 | [diff] [blame] | 105 | Delivers packets to Primary and Secondary, and then compare the responses from |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 106 | both side. Then decide whether to start a checkpoint according to some rules. |
Stefan Weil | 963e64a | 2018-07-13 14:17:27 +0200 | [diff] [blame] | 107 | Please refer to docs/colo-proxy.txt for more information. |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 108 | |
| 109 | Note: |
| 110 | HeartBeat has not been implemented yet, so you need to trigger failover process |
| 111 | by using 'x-colo-lost-heartbeat' command. |
| 112 | |
Zhang Chen | 8e64089 | 2018-09-03 12:39:00 +0800 | [diff] [blame] | 113 | == COLO operation status == |
| 114 | |
| 115 | +-----------------+ |
| 116 | | | |
| 117 | | Start COLO | |
| 118 | | | |
| 119 | +--------+--------+ |
| 120 | | |
| 121 | | Main qmp command: |
| 122 | | migrate-set-capabilities with x-colo |
| 123 | | migrate |
| 124 | | |
| 125 | v |
| 126 | +--------+--------+ |
| 127 | | | |
| 128 | | COLO running | |
| 129 | | | |
| 130 | +--------+--------+ |
| 131 | | |
| 132 | | Main qmp command: |
| 133 | | x-colo-lost-heartbeat |
| 134 | | or |
| 135 | | some error happened |
| 136 | v |
| 137 | +--------+--------+ |
| 138 | | | send qmp event: |
| 139 | | COLO failover | COLO_EXIT |
| 140 | | | |
| 141 | +-----------------+ |
| 142 | |
| 143 | COLO use the qmp command to switch and report operation status. |
| 144 | The diagram just shows the main qmp command, you can get the detail |
| 145 | in test procedure. |
| 146 | |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 147 | == Test procedure == |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 148 | Note: Here we are running both instances on the same host for testing, |
zhaolichang | 76ca4b5 | 2020-09-17 15:50:22 +0800 | [diff] [blame] | 149 | change the IP Addresses if you want to run it on two hosts. Initially |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 150 | 127.0.0.1 is the Primary Host and 127.0.0.2 is the Secondary Host. |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 151 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 152 | == Startup qemu == |
| 153 | 1. Primary: |
zhaolichang | 76ca4b5 | 2020-09-17 15:50:22 +0800 | [diff] [blame] | 154 | Note: Initially, $imagefolder/primary.qcow2 needs to be copied to all hosts. |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 155 | You don't need to change any IP's here, because 0.0.0.0 listens on any |
| 156 | interface. The chardev's with 127.0.0.1 IP's loopback to the local qemu |
| 157 | instance. |
| 158 | |
| 159 | # imagefolder="/mnt/vms/colo-test-primary" |
| 160 | |
Daniel P. Berrangé | 1bd39ea | 2021-02-16 19:10:26 +0000 | [diff] [blame] | 161 | # qemu-system-x86_64 -enable-kvm -cpu qemu64,kvmclock=on -m 512 -smp 1 -qmp stdio \ |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 162 | -device piix3-usb-uhci -device usb-tablet -name primary \ |
| 163 | -netdev tap,id=hn0,vhost=off,helper=/usr/lib/qemu/qemu-bridge-helper \ |
| 164 | -device rtl8139,id=e0,netdev=hn0 \ |
Daniel P. Berrangé | c238741 | 2021-02-16 19:10:24 +0000 | [diff] [blame] | 165 | -chardev socket,id=mirror0,host=0.0.0.0,port=9003,server=on,wait=off \ |
| 166 | -chardev socket,id=compare1,host=0.0.0.0,port=9004,server=on,wait=on \ |
| 167 | -chardev socket,id=compare0,host=127.0.0.1,port=9001,server=on,wait=off \ |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 168 | -chardev socket,id=compare0-0,host=127.0.0.1,port=9001 \ |
Daniel P. Berrangé | c238741 | 2021-02-16 19:10:24 +0000 | [diff] [blame] | 169 | -chardev socket,id=compare_out,host=127.0.0.1,port=9005,server=on,wait=off \ |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 170 | -chardev socket,id=compare_out0,host=127.0.0.1,port=9005 \ |
| 171 | -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 \ |
| 172 | -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out \ |
| 173 | -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 \ |
| 174 | -object iothread,id=iothread1 \ |
| 175 | -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,\ |
| 176 | outdev=compare_out0,iothread=iothread1 \ |
| 177 | -drive if=ide,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,\ |
| 178 | children.0.file.filename=$imagefolder/primary.qcow2,children.0.driver=qcow2 -S |
| 179 | |
| 180 | 2. Secondary: |
| 181 | Note: Active and hidden images need to be created only once and the |
| 182 | size should be the same as primary.qcow2. Again, you don't need to change |
| 183 | any IP's here, except for the $primary_ip variable. |
| 184 | |
| 185 | # imagefolder="/mnt/vms/colo-test-secondary" |
| 186 | # primary_ip=127.0.0.1 |
| 187 | |
| 188 | # qemu-img create -f qcow2 $imagefolder/secondary-active.qcow2 10G |
| 189 | |
| 190 | # qemu-img create -f qcow2 $imagefolder/secondary-hidden.qcow2 10G |
| 191 | |
Daniel P. Berrangé | 1bd39ea | 2021-02-16 19:10:26 +0000 | [diff] [blame] | 192 | # qemu-system-x86_64 -enable-kvm -cpu qemu64,kvmclock=on -m 512 -smp 1 -qmp stdio \ |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 193 | -device piix3-usb-uhci -device usb-tablet -name secondary \ |
| 194 | -netdev tap,id=hn0,vhost=off,helper=/usr/lib/qemu/qemu-bridge-helper \ |
| 195 | -device rtl8139,id=e0,netdev=hn0 \ |
Daniil Tatianin | 96e610b | 2024-10-25 10:35:25 +0300 | [diff] [blame] | 196 | -chardev socket,id=red0,host=$primary_ip,port=9003,reconnect-ms=1000 \ |
| 197 | -chardev socket,id=red1,host=$primary_ip,port=9004,reconnect-ms=1000 \ |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 198 | -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 \ |
| 199 | -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 \ |
| 200 | -object filter-rewriter,id=rew0,netdev=hn0,queue=all \ |
| 201 | -drive if=none,id=parent0,file.filename=$imagefolder/primary.qcow2,driver=qcow2 \ |
| 202 | -drive if=none,id=childs0,driver=replication,mode=secondary,file.driver=qcow2,\ |
| 203 | top-id=colo-disk0,file.file.filename=$imagefolder/secondary-active.qcow2,\ |
| 204 | file.backing.driver=qcow2,file.backing.file.filename=$imagefolder/secondary-hidden.qcow2,\ |
| 205 | file.backing.backing=parent0 \ |
| 206 | -drive if=ide,id=colo-disk0,driver=quorum,read-pattern=fifo,vote-threshold=1,\ |
| 207 | children.0=childs0 \ |
| 208 | -incoming tcp:0.0.0.0:9998 |
| 209 | |
| 210 | |
| 211 | 3. On Secondary VM's QEMU monitor, issue command |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 212 | {"execute":"qmp_capabilities"} |
Vladimir Sementsov-Ogievskiy | 121cced | 2023-04-28 22:49:28 +0300 | [diff] [blame] | 213 | {"execute": "migrate-set-capabilities", "arguments": {"capabilities": [ {"capability": "x-colo", "state": true } ] } } |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 214 | {"execute": "nbd-server-start", "arguments": {"addr": {"type": "inet", "data": {"host": "0.0.0.0", "port": "9999"} } } } |
| 215 | {"execute": "nbd-server-add", "arguments": {"device": "parent0", "writable": true } } |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 216 | |
| 217 | Note: |
| 218 | a. The qmp command nbd-server-start and nbd-server-add must be run |
| 219 | before running the qmp command migrate on primary QEMU |
| 220 | b. Active disk, hidden disk and nbd target's length should be the |
| 221 | same. |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 222 | c. It is better to put active disk and hidden disk in ramdisk. They |
| 223 | will be merged into the parent disk on failover. |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 224 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 225 | 4. On Primary VM's QEMU monitor, issue command: |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 226 | {"execute":"qmp_capabilities"} |
| 227 | {"execute": "human-monitor-command", "arguments": {"command-line": "drive_add -n buddy driver=replication,mode=primary,file.driver=nbd,file.host=127.0.0.2,file.port=9999,file.export=parent0,node-name=replication0"}} |
| 228 | {"execute": "x-blockdev-change", "arguments":{"parent": "colo-disk0", "node": "replication0" } } |
| 229 | {"execute": "migrate-set-capabilities", "arguments": {"capabilities": [ {"capability": "x-colo", "state": true } ] } } |
| 230 | {"execute": "migrate", "arguments": {"uri": "tcp:127.0.0.2:9998" } } |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 231 | |
| 232 | Note: |
| 233 | a. There should be only one NBD Client for each primary disk. |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 234 | b. The qmp command line must be run after running qmp command line in |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 235 | secondary qemu. |
| 236 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 237 | 5. After the above steps, you will see, whenever you make changes to PVM, SVM will be synced. |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 238 | You can issue command '{ "execute": "migrate-set-parameters" , "arguments":{ "x-checkpoint-delay": 2000 } }' |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 239 | to change the idle checkpoint period time |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 240 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 241 | 6. Failover test |
| 242 | You can kill one of the VMs and Failover on the surviving VM: |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 243 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 244 | If you killed the Secondary, then follow "Primary Failover". After that, |
| 245 | if you want to resume the replication, follow "Primary resume replication" |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 246 | |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 247 | If you killed the Primary, then follow "Secondary Failover". After that, |
| 248 | if you want to resume the replication, follow "Secondary resume replication" |
| 249 | |
| 250 | == Primary Failover == |
| 251 | The Secondary died, resume on the Primary |
| 252 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 253 | {"execute": "x-blockdev-change", "arguments":{ "parent": "colo-disk0", "child": "children.1"} } |
| 254 | {"execute": "human-monitor-command", "arguments":{ "command-line": "drive_del replication0" } } |
| 255 | {"execute": "object-del", "arguments":{ "id": "comp0" } } |
| 256 | {"execute": "object-del", "arguments":{ "id": "iothread1" } } |
| 257 | {"execute": "object-del", "arguments":{ "id": "m0" } } |
| 258 | {"execute": "object-del", "arguments":{ "id": "redire0" } } |
| 259 | {"execute": "object-del", "arguments":{ "id": "redire1" } } |
| 260 | {"execute": "x-colo-lost-heartbeat" } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 261 | |
| 262 | == Secondary Failover == |
| 263 | The Primary died, resume on the Secondary and prepare to become the new Primary |
| 264 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 265 | {"execute": "nbd-server-stop"} |
| 266 | {"execute": "x-colo-lost-heartbeat"} |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 267 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 268 | {"execute": "object-del", "arguments":{ "id": "f2" } } |
| 269 | {"execute": "object-del", "arguments":{ "id": "f1" } } |
| 270 | {"execute": "chardev-remove", "arguments":{ "id": "red1" } } |
| 271 | {"execute": "chardev-remove", "arguments":{ "id": "red0" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 272 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 273 | {"execute": "chardev-add", "arguments":{ "id": "mirror0", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "0.0.0.0", "port": "9003" } }, "server": true } } } } |
| 274 | {"execute": "chardev-add", "arguments":{ "id": "compare1", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "0.0.0.0", "port": "9004" } }, "server": true } } } } |
| 275 | {"execute": "chardev-add", "arguments":{ "id": "compare0", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "127.0.0.1", "port": "9001" } }, "server": true } } } } |
| 276 | {"execute": "chardev-add", "arguments":{ "id": "compare0-0", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "127.0.0.1", "port": "9001" } }, "server": false } } } } |
| 277 | {"execute": "chardev-add", "arguments":{ "id": "compare_out", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "127.0.0.1", "port": "9005" } }, "server": true } } } } |
| 278 | {"execute": "chardev-add", "arguments":{ "id": "compare_out0", "backend": {"type": "socket", "data": {"addr": { "type": "inet", "data": { "host": "127.0.0.1", "port": "9005" } }, "server": false } } } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 279 | |
| 280 | == Primary resume replication == |
| 281 | Resume replication after new Secondary is up. |
| 282 | |
| 283 | Start the new Secondary (Steps 2 and 3 above), then on the Primary: |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 284 | {"execute": "drive-mirror", "arguments":{ "device": "colo-disk0", "job-id": "resync", "target": "nbd://127.0.0.2:9999/parent0", "mode": "existing", "format": "raw", "sync": "full"} } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 285 | |
| 286 | Wait until disk is synced, then: |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 287 | {"execute": "stop"} |
| 288 | {"execute": "block-job-cancel", "arguments":{ "device": "resync"} } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 289 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 290 | {"execute": "human-monitor-command", "arguments":{ "command-line": "drive_add -n buddy driver=replication,mode=primary,file.driver=nbd,file.host=127.0.0.2,file.port=9999,file.export=parent0,node-name=replication0"}} |
| 291 | {"execute": "x-blockdev-change", "arguments":{ "parent": "colo-disk0", "node": "replication0" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 292 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 293 | {"execute": "object-add", "arguments":{ "qom-type": "filter-mirror", "id": "m0", "netdev": "hn0", "queue": "tx", "outdev": "mirror0" } } |
| 294 | {"execute": "object-add", "arguments":{ "qom-type": "filter-redirector", "id": "redire0", "netdev": "hn0", "queue": "rx", "indev": "compare_out" } } |
| 295 | {"execute": "object-add", "arguments":{ "qom-type": "filter-redirector", "id": "redire1", "netdev": "hn0", "queue": "rx", "outdev": "compare0" } } |
| 296 | {"execute": "object-add", "arguments":{ "qom-type": "iothread", "id": "iothread1" } } |
| 297 | {"execute": "object-add", "arguments":{ "qom-type": "colo-compare", "id": "comp0", "primary_in": "compare0-0", "secondary_in": "compare1", "outdev": "compare_out0", "iothread": "iothread1" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 298 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 299 | {"execute": "migrate-set-capabilities", "arguments":{ "capabilities": [ {"capability": "x-colo", "state": true } ] } } |
| 300 | {"execute": "migrate", "arguments":{ "uri": "tcp:127.0.0.2:9998" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 301 | |
| 302 | Note: |
| 303 | If this Primary previously was a Secondary, then we need to insert the |
| 304 | filters before the filter-rewriter by using the |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 305 | ""insert": "before", "position": "id=rew0"" Options. See below. |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 306 | |
| 307 | == Secondary resume replication == |
| 308 | Become Primary and resume replication after new Secondary is up. Note |
| 309 | that now 127.0.0.1 is the Secondary and 127.0.0.2 is the Primary. |
| 310 | |
| 311 | Start the new Secondary (Steps 2 and 3 above, but with primary_ip=127.0.0.2), |
| 312 | then on the old Secondary: |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 313 | {"execute": "drive-mirror", "arguments":{ "device": "colo-disk0", "job-id": "resync", "target": "nbd://127.0.0.1:9999/parent0", "mode": "existing", "format": "raw", "sync": "full"} } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 314 | |
| 315 | Wait until disk is synced, then: |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 316 | {"execute": "stop"} |
| 317 | {"execute": "block-job-cancel", "arguments":{ "device": "resync" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 318 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 319 | {"execute": "human-monitor-command", "arguments":{ "command-line": "drive_add -n buddy driver=replication,mode=primary,file.driver=nbd,file.host=127.0.0.1,file.port=9999,file.export=parent0,node-name=replication0"}} |
| 320 | {"execute": "x-blockdev-change", "arguments":{ "parent": "colo-disk0", "node": "replication0" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 321 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 322 | {"execute": "object-add", "arguments":{ "qom-type": "filter-mirror", "id": "m0", "insert": "before", "position": "id=rew0", "netdev": "hn0", "queue": "tx", "outdev": "mirror0" } } |
| 323 | {"execute": "object-add", "arguments":{ "qom-type": "filter-redirector", "id": "redire0", "insert": "before", "position": "id=rew0", "netdev": "hn0", "queue": "rx", "indev": "compare_out" } } |
| 324 | {"execute": "object-add", "arguments":{ "qom-type": "filter-redirector", "id": "redire1", "insert": "before", "position": "id=rew0", "netdev": "hn0", "queue": "rx", "outdev": "compare0" } } |
| 325 | {"execute": "object-add", "arguments":{ "qom-type": "iothread", "id": "iothread1" } } |
| 326 | {"execute": "object-add", "arguments":{ "qom-type": "colo-compare", "id": "comp0", "primary_in": "compare0-0", "secondary_in": "compare1", "outdev": "compare_out0", "iothread": "iothread1" } } |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 327 | |
Rao, Lei | eff708a | 2021-11-22 15:49:47 +0800 | [diff] [blame] | 328 | {"execute": "migrate-set-capabilities", "arguments":{ "capabilities": [ {"capability": "x-colo", "state": true } ] } } |
| 329 | {"execute": "migrate", "arguments":{ "uri": "tcp:127.0.0.1:9998" } } |
zhanghailiang | e59887d | 2016-10-27 14:43:07 +0800 | [diff] [blame] | 330 | |
| 331 | == TODO == |
Lukas Straub | 90dfe59 | 2019-10-24 16:25:57 +0200 | [diff] [blame] | 332 | 1. Support shared storage. |
| 333 | 2. Develop the heartbeat part. |
| 334 | 3. Reduce checkpoint VM’s downtime while doing checkpoint. |