Re: [Tarantool-patches] [PATCH 7/6] raft: test join to a raft cluster

[Serge Petrenko via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

06.06.2021 20:03, Vladislav Shpilevoy пишет:
> There was a bug that a new replica at join to a Raft cluster
> sometimes tried to register on a non-leader node which couldn't
> write to _cluster, so the join failed with ER_READONLY error.
>
> Now in scope of #5613 the algorithm of join-master selection is
> changed. A new node looks for writable members of the cluster to
> use a join-master. It will not choose a follower if there is a
> leader.
>
> Closes #6127

Thanks for working on this! LGTM.

> ---
>   .../unreleased/gh-6127-raft-join-new.md       |   4 +
>   test/replication/gh-6127-master1.lua          |  15 +++
>   test/replication/gh-6127-master2.lua          |  13 +++
>   test/replication/gh-6127-raft-join-new.result | 105 ++++++++++++++++++
>   .../gh-6127-raft-join-new.test.lua            |  41 +++++++
>   test/replication/gh-6127-replica.lua          |   9 ++
>   6 files changed, 187 insertions(+)
>   create mode 100644 changelogs/unreleased/gh-6127-raft-join-new.md
>   create mode 100644 test/replication/gh-6127-master1.lua
>   create mode 100644 test/replication/gh-6127-master2.lua
>   create mode 100644 test/replication/gh-6127-raft-join-new.result
>   create mode 100644 test/replication/gh-6127-raft-join-new.test.lua
>   create mode 100644 test/replication/gh-6127-replica.lua
>
> diff --git a/changelogs/unreleased/gh-6127-raft-join-new.md b/changelogs/unreleased/gh-6127-raft-join-new.md
> new file mode 100644
> index 000000000..a2d898df0
> --- /dev/null
> +++ b/changelogs/unreleased/gh-6127-raft-join-new.md
> @@ -0,0 +1,4 @@
> +## bugfix/raft
> +
> +* Fixed an error when a new replica in a Raft cluster could try to join from a
> +  follower instead of a leader and failed with an error `ER_READONLY` (gh-6127).
> diff --git a/test/replication/gh-6127-master1.lua b/test/replication/gh-6127-master1.lua
> new file mode 100644
> index 000000000..708574322
> --- /dev/null
> +++ b/test/replication/gh-6127-master1.lua
> @@ -0,0 +1,15 @@
> +#!/usr/bin/env tarantool
> +
> +require('console').listen(os.getenv('ADMIN'))
> +box.cfg({
> +    listen = 'unix/:./master1.sock',
> +    replication = {
> +        'unix/:./master1.sock',
> +        'unix/:./master2.sock'
> +    },
> +    election_mode = 'candidate',
> +    election_timeout = 0.1,
> +    instance_uuid = '10f9828d-b5d5-46a9-b698-ddac7cce5e27',
> +})
> +box.ctl.wait_rw()
> +box.schema.user.grant('guest', 'super')
> diff --git a/test/replication/gh-6127-master2.lua b/test/replication/gh-6127-master2.lua
> new file mode 100644
> index 000000000..1851070c7
> --- /dev/null
> +++ b/test/replication/gh-6127-master2.lua
> @@ -0,0 +1,13 @@
> +#!/usr/bin/env tarantool
> +
> +require('console').listen(os.getenv('ADMIN'))
> +box.cfg({
> +    listen = 'unix/:./master2.sock',
> +    replication = {
> +        'unix/:./master1.sock',
> +        'unix/:./master2.sock'
> +    },
> +    election_mode = 'voter',
> +    election_timeout = 0.1,
> +    instance_uuid = '20f9828d-b5d5-46a9-b698-ddac7cce5e27',
> +})
> diff --git a/test/replication/gh-6127-raft-join-new.result b/test/replication/gh-6127-raft-join-new.result
> new file mode 100644
> index 000000000..be6f8489b
> --- /dev/null
> +++ b/test/replication/gh-6127-raft-join-new.result
> @@ -0,0 +1,105 @@
> +-- test-run result file version 2
> +test_run = require('test_run').new()
> + | ---
> + | ...
> +
> +--
> +-- gh-6127: the algorithm selecting a node from which to join to a replicaset
> +-- should take into account who is the leader (is writable and can write to
> +-- _cluster) and who is a follower/candidate.
> +--
> +test_run:cmd('create server master1 with script="replication/gh-6127-master1.lua"')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('start server master1 with wait=False')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('create server master2 with script="replication/gh-6127-master2.lua"')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('start server master2')
> + | ---
> + | - true
> + | ...
> +
> +test_run:switch('master1')
> + | ---
> + | - true
> + | ...
> +box.cfg{election_mode = 'voter'}
> + | ---
> + | ...
> +test_run:switch('master2')
> + | ---
> + | - true
> + | ...
> +-- Perform manual election because it is faster - the automatic one still tries
> +-- to wait for 'death timeout' first which is several seconds.
> +box.cfg{                                                                        \
> +    election_mode = 'manual',                                                   \
> +    election_timeout = 0.1,                                                     \
> +}
> + | ---
> + | ...
> +box.ctl.promote()
> + | ---
> + | ...
> +box.ctl.wait_rw()
> + | ---
> + | ...
> +-- Make sure the other node received the promotion row. Vclocks now should be
> +-- equal so the new node would select only using read-only state and min UUID.
> +test_run:wait_lsn('master1', 'master2')
> + | ---
> + | ...
> +
> +-- Min UUID is master1, but it is not writable. Therefore must join from
> +-- master2.
> +test_run:cmd('create server replica with script="replication/gh-6127-replica.lua"')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('start server replica')
> + | ---
> + | - true
> + | ...
> +test_run:switch('replica')
> + | ---
> + | - true
> + | ...
> +assert(box.info.leader ~= 0)
> + | ---
> + | - true
> + | ...
> +
> +test_run:switch('default')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('stop server replica')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('delete server replica')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('stop server master2')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('delete server master2')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('stop server master1')
> + | ---
> + | - true
> + | ...
> +test_run:cmd('delete server master1')
> + | ---
> + | - true
> + | ...
> diff --git a/test/replication/gh-6127-raft-join-new.test.lua b/test/replication/gh-6127-raft-join-new.test.lua
> new file mode 100644
> index 000000000..3e0e9f226
> --- /dev/null
> +++ b/test/replication/gh-6127-raft-join-new.test.lua
> @@ -0,0 +1,41 @@
> +test_run = require('test_run').new()
> +
> +--
> +-- gh-6127: the algorithm selecting a node from which to join to a replicaset
> +-- should take into account who is the leader (is writable and can write to
> +-- _cluster) and who is a follower/candidate.
> +--
> +test_run:cmd('create server master1 with script="replication/gh-6127-master1.lua"')
> +test_run:cmd('start server master1 with wait=False')
> +test_run:cmd('create server master2 with script="replication/gh-6127-master2.lua"')
> +test_run:cmd('start server master2')
> +
> +test_run:switch('master1')
> +box.cfg{election_mode = 'voter'}
> +test_run:switch('master2')
> +-- Perform manual election because it is faster - the automatic one still tries
> +-- to wait for 'death timeout' first which is several seconds.
> +box.cfg{                                                                        \
> +    election_mode = 'manual',                                                   \
> +    election_timeout = 0.1,                                                     \
> +}
> +box.ctl.promote()
> +box.ctl.wait_rw()
> +-- Make sure the other node received the promotion row. Vclocks now should be
> +-- equal so the new node would select only using read-only state and min UUID.
> +test_run:wait_lsn('master1', 'master2')
> +
> +-- Min UUID is master1, but it is not writable. Therefore must join from
> +-- master2.
> +test_run:cmd('create server replica with script="replication/gh-6127-replica.lua"')
> +test_run:cmd('start server replica')
> +test_run:switch('replica')
> +assert(box.info.leader ~= 0)
> +
> +test_run:switch('default')
> +test_run:cmd('stop server replica')
> +test_run:cmd('delete server replica')
> +test_run:cmd('stop server master2')
> +test_run:cmd('delete server master2')
> +test_run:cmd('stop server master1')
> +test_run:cmd('delete server master1')
> diff --git a/test/replication/gh-6127-replica.lua b/test/replication/gh-6127-replica.lua
> new file mode 100644
> index 000000000..9f4c35ecd
> --- /dev/null
> +++ b/test/replication/gh-6127-replica.lua
> @@ -0,0 +1,9 @@
> +#!/usr/bin/env tarantool
> +
> +require('console').listen(os.getenv('ADMIN'))
> +box.cfg({
> +    replication = {
> +        'unix/:./master1.sock',
> +        'unix/:./master2.sock'
> +    },
> +})

-- 
Serge Petrenko