Distcc/ja

Distcc is a program designed to distribute compiling tasks across a network to participating hosts. It is comprised of a server,, and a client program,. Distcc can work transparently with ccache, Portage, and Automake with a little setup.

When planning on using to help bootstrap a Gentoo installation, make sure to read Using distcc to bootstrap.

インストール
Before configuring, let's first look into the installation of the package on all hosts.

全てのホストで必要なこと
In order to use, all of the computers on the network need to have the same GCC versions. For example, mixing 3.3.x (where the x varies) is okay, but mixing 3.3.x with 3.2.x may result in compilation errors or runtime errors.

ソフトウェアのインストール
Distcc ships with a graphical monitor to monitor tasks that a computer is sending away for compilation. This monitor is enabled when the  USE flag is set.

After configuring the USE setting, install the package:

distcc デーモンの自動起動
In order to have started automatically, follow the next set of instructions, depending on the init system used.

OpenRC をご使用中の場合
Edit and make sure to set the   directive to allow only trusted clients. For added security, use the  directive to tell the  daemon what IP to listen on (for multi-homed systems). More information on security can be found at Distcc security notes.

The following example allows the distcc clients running at  and   to connect to the  server running locally:

Now start the daemon on all the participating computers:

systemd をご使用中の場合
を編集して、CIDRフォーマットにて許可するクライアントを追加してください. 例をあげますと:

このような変更した後は、ユニット・ファイルをリロードしましょう.

Enable auto-starting and then start the service:

設定
Let's now look into the configuration of.

参加するホストを記述する
Use the command to set the list of hosts.

The following is an example list of host definitions. In most cases, variants of lines 1 and 2 suffice. The latter uses the  syntax to inform  about the maximum amount of jobs to be launched on this node. More information about the syntax used in lines 3 and 4 can be found in the distcc manual page.

There are also several other methods of setting up hosts. See the man page  for more details.

ローカルマシンでもコンパイル作業をさせたいのなら、ホストのリストに  と記入しましょう. 逆に、ローカルマシンにコンパイル作業をさせたくない場合には、リストから外しましょう. 遅いマシンでlocalhostを設定してると、実際すべてのことが遅くなってしまうでしょう. また、設定したものをテストするのも忘れないでください.

Let's configure to use the hosts mentioned on the first line in the example:

Portageでdistccを使用する
Setting up Portage to use is easy. It is a matter of enabling the feature, and setting a decent value for the number of simultaneous build jobs (as  increases the amount of build resources).

Set the MAKEOPTS variable and FEATURES variable as shown below.

一般的な戦略としては、
 * の値を「トータルの」(ローカルとリモートの)CPUコアの個数の2倍 + 1に設定し、
 * の値を「ローカルの」CPUコアの個数に設定します.

The use of  in the MAKEOPTS variable will prevent spawning too many tasks when some of the  cluster hosts are unavailable (increasing the amount of simultaneous jobs on the other systems) or when an ebuild is configured to disallow remote builds (such as with gcc). This is accomplished by refusing to start additional jobs when the system load is at or above the value of.

For instance, when there are two quad-core host PCs running and the local PC has a dual core CPU, then the MAKEOPTS variable could look like this:

While editing the file, make sure that it does not have   in the CFLAGS or CXXFLAGS variables. will not distribute work to other machines if  is set to. The appropriate  value can be obtained by running the following command:

See Inlining  for distcc for more information.

automake で distcc を使用する
This is, in some cases, easier than the Portage setup. All that is needed is to update the PATH variable to include in front of the directory that contains. However, there is a caveat. If is used, then put the  location after the  one:

Put this in the user's or equivalent file to have the PATH set every time the user logs in, or set it globally through an  file.

Instead of calling alone, add in   (where   is an integer). The value of  depends on the network and the types of computers that are used to compile. A heuristic approach to the right value is given earlier in this article.

ブートストラップにdistccを使う
Using to bootstrap (i.e. build a working toolchain before installing the remainder of the system) requires some additional steps to take.

Step 1: Portage の設定
Boot the new box with a Gentoo Linux LiveCD and follow the installation instructions, while keeping track of the instructions in the Gentoo FAQ for information about bootstrapping. Then configure Portage to use :

Update the  variable in the installation session as well:

Step 2: distcc をゲット
Install :

Step 3: distcc のセッティング
Run to setup distcc; substitute the   in the example with the IP addresses or hostnames of the participating nodes.

Distcc is now set up to bootstrap! Continue with the proper installation instructions and do not forget to run after running. This is to make sure that all of the necessary dependencies are installed.

Distcc に付属するツール群
The application has additional features and applications to support working in a  environment.

Distcc の監視
Distcc ships with two monitoring utilities. The text-based monitoring utility is always built and is called. Running it for the first time can be a bit confusing, but it is really quite easy to use. If the program is run with no parameter it will run just once. However, if it is passed a number it will update every  seconds, where   is the argument that was passed.

The other monitoring utility is only enabled when the  USE flag is set. This one is GTK+ based, runs in an X environment, and it is quite lovely. For Gentoo, the GUI monitor has been renamed to to make it less confusing (it is originally called ).

To monitor Portage's usage:

A trick is to set DISTCC_DIR in environment variables:

ここで、環境を更新します:

ようやく、GUIアプリケーションを開始することができます:

distccの通信に SSH を使いたい時
Setting up distcc via SSH includes some pitfalls. First, generate an SSH key pair without password setup. Be aware that portage compiles programs as the Portage user (or as root if  is not set). The home folder of the Portage user is, which means the keys need to be stored in

Second, create a section for each host in the SSH configuration file:

Send the public key to each compilation node:

Also make sure that each host is available in the file:

Fix the file ownership as follows:

To set up the hosts  and , run:

Please note the  (@ sign), which specifies ssh hosts for distcc.

Finally, tell which SSH binary to use:

It is not necessary to run the initscript on the hosts when  communicates via SSH.

トラブルシューティング
If a problem occurs while using, then this section might help in resolving the problem.

ERROR: failed to open
2015年1月22日以降、emergeすると に適切な  ファイルを作るのに失敗します. これは、 distcc ver.3.1-r8 のみに起こることが明らかにされています. このバグは現在修正中ですが(参照:)、手作業でそのログファイルを作成し、適切な所有者を設定し、distccデーモンを再起動することで何とかうまく動くようにできます.

Next update the path of the  configuration file in  to the  directory created in the step before:

最後に distccd サービスを再起動します.

distccをつかえないパッケージもあります
As various packages are installed, users will notice that some of them aren't being distributed (and aren't being built in parallel). This may happen because the package' doesn't support parallel operations, or the maintainer of the ebuild has explicitly disabled parallel operations due to a known problem.

Sometimes might cause a package to fail to compile. If this happens, please report it.

GCC のバージョンが混在する場合
If the environment hosts different GCC versions, there will likely be very weird problems. The solution is to make certain all hosts have the same GCC version.

Recent Portage updates have made Portage use  (minus gcc) instead of. This means that if i686 machines are mixed with other types (i386, i586) then the builds will run into troubles. A workaround for this may be to run:

It is also possible to set the CC and CXX variables in to the values list in the command above.

-march=native
Starting with GCC 4.3.0, the compiler supports the  option which turns on CPU auto-detection and optimizations that are worth being enabled on the processor on which GCC is running. This creates a problem when using because it allows the mixing of code optimized for different processors. For example, running with   on a system that has an AMD Athlon processor and doing the same on another system that has an Intel Pentium processor will mix code compiled on both processors together.

Heed the following warning:

To know the flags that GCC would enable when called with, execute the following:

参考

 * The DistCC Cross-compiling guide explains how using one architecture to build programs for another architecture is done through . This can be as simple as using an Athlon (i686) to build a program for a K6-2 (i586), or using a SPARC to build a program for a PowerPC.

外部の情報

 * Inlining  for distcc
 * Distcc homepage