Skip reverse DNS lookups

[yosifkit]

fixes #52

[yosifkit]

$ ./generate-stackbrew-library.sh | sed -r 's/docker-library/infosiftr/' > mysql
$ ./bashbrew/bashbrew.sh build ../mysql/mysql
Cloning mysql (git://github.com/infosiftr/mysql) ...
Processing mysql:5.5.45 ...
Processing mysql:5.5 ...
Processing mysql:5.6.26 ...
Processing mysql:5.6 ...
Processing mysql:5 ...
Processing mysql:latest ...
Processing mysql:5.7.7-rc ...
Processing mysql:5.7.7 ...
Processing mysql:5.7 ...
$ ./bashbrew/bashbrew.sh list --uniq ../mysql/mysql | xargs ./test/run.sh
testing mysql:5.5.45
    'utc' [1/4]...passed
    'cve-2014--shellshock' [2/4]...passed
    'no-hard-coded-passwords' [3/4]...passed
    'mysql-basics' [4/4]...passed
testing mysql:5.6.26
    'utc' [1/4]...passed
    'cve-2014--shellshock' [2/4]...passed
    'no-hard-coded-passwords' [3/4]...passed
    'mysql-basics' [4/4]...passed
testing mysql:5.7.7-rc
    'utc' [1/4]...passed
    'cve-2014--shellshock' [2/4]...passed
    'no-hard-coded-passwords' [3/4]...passed
    'mysql-basics' [4/4]...mysqld failed to accept connections in a reasonable amount of time!
ERROR 2003 (HY000): Can't connect to MySQL server on 'mysql' (111)
failed

[tianon]

This regex condition could instead be $1 == "[mysqld]".

[tianon]

I'm definitely a fan of skipping these by default for the image, especially since so many users will be behind at least Docker's NAT by default, so incoming connections won't resolve and we're just wasting precious time.

ping @ltangvald; what're your thoughts here?

[yosifkit]

This leaves the my.cnf having this diff from it's previous state:

 [mysqld]
+skip-host-cache
+skip-name-resolve
 user       = mysql
 pid-file   = /var/run/mysqld/mysqld.pid
 socket     = /var/run/mysqld/mysqld.sock

[shofetim]

👍

[tianon]

LGTM

[joshunger]

I believe this breaks permissions/grants in certain cases? Can this be a setting? Or, how do you override "skip-name-resolve" in a file in the conf.d directory?

[tianon]

Sorry for the delay, @joshunger; I would imagine something like skip-name-resolve = off or skip-name-resolve = false should work (given that the config is supposed to be key-value pairs), but I haven't tested to verify that. If that doesn't work, the only other thing I can think of (besides overwriting this provided file completely) is to do something like RUN sed -i '/skip-name-resolve/d' ... to remove the line.