Added cluster setup using go processes

[arindamnayak]

Signed-off-by: Arindam Nayak [email protected]

Added cluster setup using go processes (vttablet, vtctld, vtgate etc.. processes).
Added clustertest to verify if cluster setup is working.
Migrated 2 of go/vt/vtgate/endtoend/ test to use the new cluster setup.

[deepthi]

We should be able to run the tests in local environment, not just in docker.

[deepthi]

W1030 19:39:55.158670   23792 plugin_mysql_server.go:426] Found existent socket when trying to create new unix mysql listener: /tmp/mysql.sock, attempting to clean up

How are you ensuring that when we start more than one vttablet+mysql, each mysql is running on a different socket?

[deepthi]

I have verified that I can run go test on my dev machine, and it works fine, no docker necessary.

[arindamnayak]

/tmp/mysql.sock,

We execute mysqlctl here, there we specify the tablet_uid which is unique for each tablets, at that point different vt_0000XXX directory is created, where mysql socket file is created under such tablet directories. The following lines , create tablet and uses the same tablet_uid created just before, which ensures the corresponding tablet uses the socket file under that directory.

Regarding the warning, /tmp/mysql.sock, attempting to clean up, I have never got it (not even in docker), but in ajeet got such warning. I think it is related to the mysql connection we make for testing e.g. here. I have also noticed such warning (I mean earlier, outside of vitess project) when I try do mysql connection from console (mysql -uroot -p).

[deepthi]

E1031 17:08:00.560412   30510 cluster_process.go:121] mkdir /home/go/vtdataroot/backups: file exists
E1031 17:09:15.040979   30801 cluster_process.go:121] mkdir /home/go/vtdataroot/tmp: file exists

when these errors occur, the tests fail. Can we try to mkdir only if the directory doesn't already exist?

[arindamnayak]

e direc

@deepthi , this is already taken care, please check this file. Also I changed the code to not use tmp directory, currently it uses tmp_{random_id} as directory name, so that parallel execution won't conflict.For backups directory, it check if directory is present then don't create it.

Please take latest update and then run the tests.

[sougou]

Nice work. Very readable code. I caught one issue on the random number generation. I'm surprised any tests ran successfully in parallel.

[sougou]

This is not as random as you think. At minimum, you have to call rand.Seed. Otherwise, all processes will generate the exact same sequence of random numbers.

I'm also worried about the possibility of collisions even after seeding. But I don't have an elegant answer right now.

[arindamnayak]

Currently all these type of tests run sequentially - check here. However, I noticed that for every run of test, the processes generated with different numbers for port even in travis and github workflow (just verified those in execution log) as well as in local environment (Whereas it should have generated same seq of random numbers for every run). Anyway I will try with rand.Seed to add some randomness.

Note: Here it can be seen that for every test, the etcd uses different port (same applicable for each process), 1st, 2nd , 3rd.

[arindamnayak]

Added rand.seed in the recent commit.

[deepthi]

@morgo how do we know which version of mysql is being used here?

[morgo]

It is the one included in ubuntu-latest, so likely 8.0. I can change it to MySQL 5.7 from Oracle repos. For the local-example it does the same, but a matrix build probably makes more sense so we catch both.

[morgo]

I looked into this further, it is 5.7:

mysql-client is already the newest version (5.7.27-0ubuntu0.18.04.1).
mysql-server is already the newest version (5.7.27-0ubuntu0.18.04.1).

The ubuntu-latest is 18.04. Assuming GitHub plans to bump this with new lts releases, this will change to 20.04, and MySQL 8.0 in April 2020. The fix then is to switch to the MySQL team repos, or consider upgrading our testsuite. Since MySQL 8.0 initializes slower, we will most likely chose the repo switch:

        wget https://dev.mysql.com/get/mysql-apt-config_0.8.13-1_all.deb
        sudo apt install -y ./mysql-apt-config_0.8*
        sudo sed -i 's/mysql-8.0/mysql-5.7/' /etc/apt/sources.list.d/mysql.list
        sudo apt-get update
        sudo apt-get install mysql-community-server mysql-community-client

Looks resolved.