[Nix-dev] How to use MySQL

[Tomasz Czyż]

Linus,

by installing it with nix-env you install only the binary and all
application execution is in user hands. By using "service" in
configuration.nix you actually start a daemon (like /etc/init.d/mysql in
ubuntu for instance).

If you want to start it in user space you have to follow exactly the same
steps as in other distros when you are not using /etc/init.d/ or upstart or
whatever system level daemon manager.

If you want to try to reproduce what "service" is doing in your userspace,
you can check config of service and try to execture those commands in
userspace:

https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/databases/mysql.nix

So you can see, that configuration is generated first and then service is
started with

serviceConfig.ExecStart = "${mysql}/bin/mysqld
--defaults-extra-file=${myCnf} ${mysqldOptions}";


2016-10-03 9:21 GMT+01:00 Linus Arver <linusarver at gmail.com>:

> Hello all,
>
> I want to install and use MySQL on NixOS, but am not sure how to
> proceed. I've managed to do
>
>     nix-env -iA nixos.mysql55
>
> but trying to get it to run is difficult. Here is what I tried:
>
>     [月 03 0:50:47] - l_k0 ~/prog/sqfmm/mysql
>      > mysql
>     ERROR 2002 (HY000): Can't connect to local MySQL server through socket
> '/run/mysqld/mysqld.sock' (2)
>     [月 03 0:50:53] 1 - l_k0 ~/prog/sqfmm/mysql
>      > systemctl start mysqld
>     ==== AUTHENTICATING FOR org.freedesktop.systemd1.manage-units ===
>     Authentication is required to start 'mysqld.service'.
>     Multiple identities can be used for authentication:
>      1.  System administrator (root)
>      2.  Linus Arver (l)
>     Choose identity to authenticate as (1-2): 2
>     Password:
>     ==== AUTHENTICATION COMPLETE ===
>     Failed to start mysqld.service: Unit mysqld.service not found.
>     [月 03 0:52:33] 5 - l_k0 ~/prog/sqfmm/mysql
>      > systemctl start mysql
>     ==== AUTHENTICATING FOR org.freedesktop.systemd1.manage-units ===
>     Authentication is required to start 'mysql.service'.
>     Multiple identities can be used for authentication:
>      1.  System administrator (root)
>      2.  Linus Arver (l)
>     Choose identity to authenticate as (1-2): 2
>     Password:
>     ==== AUTHENTICATION COMPLETE ===
>     Failed to start mysql.service: Unit mysql.service not found.
>     [月 03 0:52:57] 5 - l_k0 ~/prog/sqfmm/mysql
>      > mysqld
>     161003  0:53:16 [Note] mysqld (mysqld 5.5.50) starting as process
> 12363 ...
>     161003  0:53:16 [Warning] Can't create test file
> /var/lib/mysql/k0.lower-test
>     161003  0:53:16 [Warning] Can't create test file
> /var/lib/mysql/k0.lower-test
>     mysqld: Can't change dir to '/var/lib/mysql/' (Errcode: 2)
>     161003  0:53:16 [ERROR] Aborting
>
>     161003  0:53:16 [Note] mysqld: Shutdown complete
>
>     [月 03 0:53:16] 1 - l_k0 ~/prog/sqfmm/mysql
>      > mysqld_safe
>     161003 00:54:16 mysqld_safe Logging to '/var/lib/mysql/k0.err'.
>     touch: cannot touch '/var/lib/mysql/k0.err': No such file or directory
>     chmod: cannot access '/var/lib/mysql/k0.err': No such file or directory
>     mkdir: cannot create directory ‘/run/mysqld’: Permission denied
>     chown: invalid user: ‘mysql’
>     chmod: cannot access '/run/mysqld': No such file or directory
>     161003 00:54:16 mysqld_safe Starting mysqld daemon with databases from
> /var/lib/mysql
>     /home/l/.nix-profile/bin/mysqld_safe: line 128:
> /var/lib/mysql/k0.err: No such file or directory
>     /home/l/.nix-profile/bin/mysqld_safe: line 165:
> /var/lib/mysql/k0.err: No such file or directory
>     touch: cannot touch '/var/lib/mysql/k0.err': No such file or directory
>     chown: invalid user: ‘mysql’
>     chmod: cannot access '/var/lib/mysql/k0.err': No such file or directory
>     161003 00:54:16 mysqld_safe mysqld from pid file /var/lib/mysql/k0.pid
> ended
>     /home/l/.nix-profile/bin/mysqld_safe: line 128:
> /var/lib/mysql/k0.err: No such file or directory
>
> The attempt to run *mysqld_safe* was taken from the official docs at
> http://dev.mysql.com/doc/refman/5.6/en/starting-server.html.
>
> I see that there are several configuration options for MySQL
> (services.mysql.*) defined in the NixOS manual
> (https://nixos.org/nixos/manual/options.html#opt-services.mysql.enable)
> but this seems to be for enabling it as a service that starts
> unconditionally on every boot (configuration.nix), which I want to avoid.
>
> How do I start MySQL without touching configuration.nix? If
> configuration.nix is the only sane/preferred way to use MySQL on NixOS,
> then is there a resource/wiki/blogpost that discusses a minimal example?
> I don't mind trial-and-error with editing my system configs but seeing a
> second-hand account of the entire process would be very helpful.
>
> Please forgive me if I have missed any obvious documentation.
>
> Best,
> Linus
> _______________________________________________
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> nix-dev at lists.science.uu.nl
> http://lists.science.uu.nl/mailman/listinfo/nix-dev
>



-- 
Tomasz Czyż
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