ovn-central raft HA (by quqi99)

Posted 2022-10-25 quqi99

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作者：张华发表于：2022-10-12
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What’s raft

RAFT(https://raft.github.io/)是一种致性算法，它有三种节点：

Follower - This is first state when node start.
Candidate - If no leader then start election.
Leader - If get enough vote then it become leader and all other nodes followers.

使用RAFT做做ovn-central HA的作用相当于haproxy或pacemaker (see https://bugs.launchpad.net/neutron/+bug/1969354/comments/3 )

Set up ovn-central raft HA env

基于3个LXD容器快速搭建ovn-central raft HA环境.

cd ~ && lxc launch faster:ubuntu/focal v1
lxc launch faster:ubuntu/focal v2
lxc launch faster:ubuntu/focal v3
#the subnet is 192.168.121.0/24
lxc config device override v1 eth0 ipv4.address=192.168.121.2
lxc config device override v2 eth0 ipv4.address=192.168.121.3
lxc config device override v3 eth0 ipv4.address=192.168.121.4
lxc stop v1 && lxc start v1 && lxc stop v2 && lxc start v2 && lxc stop v3 && lxc start v3

#on v1
lxc exec `lxc list |grep v1 |awk -F '|' 'print $2'` bash
sudo apt install ovn-central -y
cat << EOF |tee /etc/default/ovn-central
OVN_CTL_OPTS= \\
  --db-nb-addr=192.168.121.2 \\
  --db-sb-addr=192.168.121.2 \\
  --db-nb-cluster-local-addr=192.168.121.2 \\
  --db-sb-cluster-local-addr=192.168.121.2 \\
  --db-nb-create-insecure-remote=yes \\
  --db-sb-create-insecure-remote=yes \\
  --ovn-northd-nb-db=tcp:192.168.121.2:6641,tcp:192.168.121.3:6641,tcp:192.168.121.4:6641 \\
  --ovn-northd-sb-db=tcp:192.168.121.2:6642,tcp:192.168.121.3:6642,tcp:192.168.121.4:6642
EOF
rm -rf /var/lib/ovn/* && rm -rf /var/lib/ovn/.ovn*
systemctl restart ovn-central
root@v1:~# ovs-appctl -t /var/run/ovn/ovnnb_db.ctl cluster/status OVN_Northbound
6943
Name: OVN_Northbound
Cluster ID: 51b9 (51b9f953-989f-4f90-9add-73dbabe3fe06)
Server ID: 6943 (69432f05-2d37-44fd-8869-2ec365bb0b4c)
Address: tcp:192.168.121.2:6643
Status: cluster member
Role: leader
Term: 2
Leader: self
Vote: self
Election timer: 1000
Log: [2, 5]
Entries not yet committed: 0
Entries not yet applied: 0
Connections: <-0000 <-0000
Servers:
    6943 (6943 at tcp:192.168.121.2:6643) (self) next_index=4 match_index=4

#on v2
lxc exec `lxc list |grep v2 |awk -F '|' 'print $2'` bash
sudo apt install ovn-central -y
cat << EOF |tee /etc/default/ovn-central
OVN_CTL_OPTS= \\
  --db-nb-addr=192.168.121.3 \\
  --db-sb-addr=192.168.121.3 \\
  --db-nb-cluster-local-addr=192.168.121.3 \\
  --db-sb-cluster-local-addr=192.168.121.3 \\
  --db-nb-create-insecure-remote=yes \\
  --db-sb-create-insecure-remote=yes \\
  --ovn-northd-nb-db=tcp:192.168.121.2:6641,tcp:192.168.121.3:6641,tcp:192.168.121.4:6641 \\
  --ovn-northd-sb-db=tcp:192.168.121.2:6642,tcp:192.168.121.3:6642,tcp:192.168.121.4:6642 \\
  --db-nb-cluster-remote-addr=192.168.121.2 \\
  --db-sb-cluster-remote-addr=192.168.121.2
EOF
rm -rf /var/lib/ovn/* && rm -rf /var/lib/ovn/.ovn*
systemctl restart ovn-central
root@v2:~# ovs-appctl -t /var/run/ovn/ovnnb_db.ctl cluster/status OVN_Northbound
158b
Name: OVN_Northbound
Cluster ID: 51b9 (51b9f953-989f-4f90-9add-73dbabe3fe06)
Server ID: 158b (158b0aea-ba5d-42e0-b69b-2fc05204f622)
Address: tcp:192.168.121.3:6643
Status: cluster member
Role: follower
Term: 2
Leader: 6943
Vote: unknown
Election timer: 1000
Log: [2, 7]
Entries not yet committed: 0
Entries not yet applied: 0
Connections: ->0000 <-6943
Servers:
    6943 (6943 at tcp:192.168.121.2:6643)
    158b (158b at tcp:192.168.121.3:6643) (self)


#on v3
lxc exec `lxc list |grep v3 |awk -F '|' 'print $2'` bash
sudo apt install ovn-central -y
cat << EOF |tee /etc/default/ovn-central
OVN_CTL_OPTS= \\
  --db-nb-addr=192.168.121.4 \\
  --db-sb-addr=192.168.121.4 \\
  --db-nb-cluster-local-addr=192.168.121.4 \\
  --db-sb-cluster-local-addr=192.168.121.4 \\
  --db-nb-create-insecure-remote=yes \\
  --db-sb-create-insecure-remote=yes \\
  --ovn-northd-nb-db=tcp:192.168.121.2:6641,tcp:192.168.121.3:6641,tcp:192.168.121.4:6641 \\
  --ovn-northd-sb-db=tcp:192.168.121.2:6642,tcp:192.168.121.3:6642,tcp:192.168.121.4:6642 \\
  --db-nb-cluster-remote-addr=192.168.121.2 \\
  --db-sb-cluster-remote-addr=192.168.121.2
EOF
rm -rf /var/lib/ovn/* && rm -rf /var/lib/ovn/.ovn*
systemctl restart ovn-central
root@v3:~# ovs-appctl -t /var/run/ovn/ovnnb_db.ctl cluster/status OVN_Northbound
298d
Name: OVN_Northbound
Cluster ID: 51b9 (51b9f953-989f-4f90-9add-73dbabe3fe06)
Server ID: 298d (298de33b-1b92-47c4-95aa-ebcf8e80f567)
Address: tcp:192.168.121.4:6643
Status: cluster member
Role: follower
Term: 2
Leader: 6943
Vote: unknown

Election timer: 1000
Log: [2, 8]
Entries not yet committed: 0
Entries not yet applied: 0
Connections: ->0000 ->158b <-6943 <-158b
Servers:
    6943 (6943 at tcp:192.168.121.2:6643)
    158b (158b at tcp:192.168.121.3:6643)
    298d (298d at tcp:192.168.121.4:6643) (self)
OVN_NB_DB=tcp:192.168.121.2:6641,tcp:192.168.121.3:6641,tcp:192.168.121.4:6641 ovn-nbctl show
OVN_SB_DB=tcp:192.168.121.2:6642,tcp:192.168.121.3:6642,tcp:192.168.121.4:6642 ovn-sbctl show

Cluster Failover Testing

做一个failover的测试，停掉容器v1 (lxc stop v1), 会在v2与v3上看到如下日志，现在v2变成了leader，并且Term由2变成了3.

root@v2:~# tail -f /var/log/ovn/ovsdb-server-nb.log
2022-10-12T03:38:18.092Z|00085|raft|INFO|received leadership transfer from 6943 in term 2
2022-10-12T03:38:18.092Z|00086|raft|INFO|term 3: starting election
2022-10-12T03:38:18.095Z|00088|raft|INFO|term 3: elected leader by 2+ of 3 servers

root@v3:~# tail -f /var/log/ovn/ovsdb-server-nb.log
2022-10-12T03:38:18.095Z|00021|raft|INFO|server 158b is leader for term 3

root@v2:~# ovs-appctl -t /var/run/ovn/ovnnb_db.ctl cluster/status OVN_Northbound
158b
Name: OVN_Northbound
Cluster ID: 51b9 (51b9f953-989f-4f90-9add-73dbabe3fe06)
Server ID: 158b (158b0aea-ba5d-42e0-b69b-2fc05204f622)
Address: tcp:192.168.121.3:6643
Status: cluster member
Role: leader
Term: 3
Leader: self
Vote: self
Election timer: 1000
Log: [2, 9]
Entries not yet committed: 0
Entries not yet applied: 0
Connections: (->0000) <-298d ->298d
Servers:
    6943 (6943 at tcp:192.168.121.2:6643) next_index=9 match_index=0
    158b (158b at tcp:192.168.121.3:6643) (self) next_index=8 match_index=8
    298d (298d at tcp:192.168.121.4:6643) next_index=9 match_index=8

set inactivity-probe for raft port (6644)

ovn-sbctl list connection
#ovn-sbctl --no-leader-only list connection
ovn-sbctl --inactivity-probe=30000 set-connection pssl:6642 pssl:6644 pssl:16642
ovn-sbctl --inactivity-probe=30000 set-connection pssl:6642 pssl:6644 pssl:16642 punix:/var/run/ovn/ovnsb_db.sock
ovn-sbctl --inactivity-probe=30000 set-connection read-write role="ovn-controller" pssl:6642 read-write role="ovn-controller" pssl:6644 pssl:16642

或者使用下面的（它等价于：ovn-nbctl --inactivity-probe=57 set-connection pssl:6642 pssl:6644）

#https://mail.openvswitch.org/pipermail/ovs-discuss/2020-February/049743.html
#https://opendev.org/x/charm-ovn-central/commit/9dcd53bb75805ff733c8f10b99724ea16a2b5f25
ovn-sbctl -- --id=@connection create Connection target="pssl\\:6644" inactivity_probe=55 -- set SB_Global . connections=@connection
ovn-sbctl set connection . inactivity_probe=56

#above 'set SB_Global' will delete all then create one new, here 'add SB_Global' is only to add one new
ovn-sbctl -- --id=@connection create Connection target="pssl\\:6648" -- add SB_Global . connections @connection
ovn-sbctl --inactivity-probe=30000 set-connection pssl:6648

use ovsdb-tool to set up cluster

https://mail.openvswitch.org/pipermail/ovs-discuss/2020-February/049743.html
使用下列命令来用ovsdb-tool来创建cluster时刚开始未成功（在v2上用’ovs-appctl -t /var/run/ovn/ovnnb_db.ctl cluster/status OVN_Northbound’ 看到＇Remotes for joining: tcp:192.168.121.4:6643 tcp:192.168.121.3:6643＇无法加入cluster），那是因为在v2上运行’join-cluster’命令时v2的ip (192.168.121.3:6644)应该写在最前面,　所以对于v2它应该是" tcp:192.168.121.3:6644 tcp:192.168.121.2:6644 tcp:192.168.121.4:6644"，而不是" tcp:192.168.121.2:6644 tcp:192.168.121.3:6644 tcp:192.168.121.4:6644"

#reset env in all nodes(v1, v2, v3)
systemctl stop ovn-central
rm -rf /var/lib/ovn/* && rm -rf /var/lib/ovn/.ovn*
rm -rf /etc/default/ovn-central

# on v1
rm -rf /var/lib/openvswitch/ovn*b_db.db
ovsdb-tool create-cluster /var/lib/openvswitch/ovnsb_db.db /usr/share/ovn/ovn-sb.ovsschema tcp:192.168.121.2:6644
ovsdb-tool create-cluster /var/lib/openvswitch/ovnnb_db.db /usr/share/ovn/ovn-nb.ovsschema tcp:192.168.121.2:6643

# on v2
rm -rf /var/lib/openvswitch/ovn*b_db.db
ovsdb-tool join-cluster /var/lib/openvswitch/ovnsb_db.db OVN_Southbound tcp:192.168.121.3:6644 tcp:192.168.121.2:6644 tcp:192.168.121.4:6644
ovsdb-tool join-cluster /var/lib/openvswitch/ovnnb_db.db OVN_Northbound tcp:192.168.121.3:6643 tcp:192.168.121.2:6643 tcp:192.168.121.4:6643

# on v3
rm -rf /var/lib/openvswitch/ovn*b_db.db
ovsdb-tool join-cluster /var/lib/openvswitch/ovnsb_db.db OVN_Southbound tcp:192.168.121.4:6644 tcp:192.168.121.2:6644 tcp:192.168.121.3:6644
ovsdb-tool join-cluster /var/lib/openvswitch/ovnnb_db.db OVN_Northbound tcp:192.168.121.4:6643 tcp:192.168.121.2:6643 tcp:192.168.121.3:6643

# then append the following content in /etc/default/ovn-central, finally restart ovn-central
--db-nb-file=/var/lib/openvswitch/ovnnb_db.db --db-sb-file=/var/lib/openvswitch/ovnsb_db.db

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