composer安装fxp插件时候提示内存不足且没有交换空间的解决办法

The following exception is caused by a lack of memory and not having swap
Check https://getcomposer.org/doc/articles/troubleshooting.md#proc-open-for details

 http://www.linuxidc.com/Linux/2010-09/28915.htm ubuntu增加交换空间的步骤

提供了创建交换空间的方法

proc_open(): fork failed errors#

If composer shows proc_open() fork failed on some commands:

PHP Fatal error: Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar

This could be happening because the VPS runs out of memory and has no Swap space enabled.

free -m

total used free shared buffers cached
Mem: 2048 357 1690 0 0 237
-/+ buffers/cache: 119 1928
Swap: 0 0 0

To enable the swap you can use for example:

/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1

下面是整个过程

root@tyr:/var/www/html/laravel# ./composer.phar global require "laravel/installer=~1.1"
Changed current directory to /root/.composer
PHP Fatal error:  Call to undefined method FxpComposerAssetPluginPackageVersionVersionParser::parseLinks() in /root/.composer/vendor/fxp/composer-asset-plugin/Repository/VcsPackageFilter.php on line 272

Fatal error: Call to undefined method FxpComposerAssetPluginPackageVersionVersionParser::parseLinks() in /root/.composer/vendor/fxp/composer-asset-plugin/Repository/VcsPackageFilter.php on line 272
root@tyr:/var/www/html/laravel# composer require "fxp/composer-asset-plugin:~1.0"
./composer.json has been created
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Installing fxp/composer-asset-plugin (v1.0.3)
    Downloading: 100%         
The following exception is caused by a lack of memory and not having swap configured
Check https://getcomposer.org/doc/articles/troubleshooting.md#proc-open-fork-failed-errors for details
PHP Fatal error:  Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php:974
Stack trace:
#0 [internal function]: ComposerUtilErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///usr/loc...', 974, Array)
#1 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(974): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
#2 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(784): SymfonyComponentConsoleApplication->getSttyColumns()
#3 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(745): SymfonyComponentConsoleApplication->getTerminalDimensions()
#4 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(675): SymfonyComponentConsoleApplication->getTerminalWidth()
#5 phar:///usr/local/bin/com in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php on line 974

Fatal error: Uncaught exception 'ErrorException' with message 'proc_open(): fork failed - Cannot allocate memory' in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php:974
Stack trace:
#0 [internal function]: ComposerUtilErrorHandler::handle(2, 'proc_open(): fo...', 'phar:///usr/loc...', 974, Array)
#1 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(974): proc_open('stty -a | grep ...', Array, NULL, NULL, NULL, Array)
#2 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(784): SymfonyComponentConsoleApplication->getSttyColumns()
#3 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(745): SymfonyComponentConsoleApplication->getTerminalDimensions()
#4 phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php(675): SymfonyComponentConsoleApplication->getTerminalWidth()
#5 phar:///usr/local/bin/com in phar:///usr/local/bin/composer/vendor/symfony/console/Symfony/Component/Console/Application.php on line 974
root@tyr:/var/www/html/laravel# free -m
             total       used       free     shared    buffers     cached
Mem:           488        414         74         24          1         71
-/+ buffers/cache:        340        147
Swap:            0          0          0
root@tyr:/var/www/html/laravel# /bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB) copied, 25.3413 s, 42.4 MB/s
root@tyr:/var/www/html/laravel# /sbin/mkswap /var/swap.1
Setting up swapspace version 1, size = 1048572 KiB
no label, UUID=60a9b908-925a-4161-8fca-7ae2d5a76154
root@tyr:/var/www/html/laravel# /sbin/swapon /var/swap.1
root@tyr:/var/www/html/laravel# free -m
             total       used       free     shared    buffers     cached
Mem:           488        474         13         24          2        127
-/+ buffers/cache:        344        143
Swap:         1023          0       1023
root@tyr:/var/www/html/laravel# composer require "fxp/composer-asset-plugin:~1.0"
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
  - Installing fxp/composer-asset-plugin (v1.0.3)
    Loading from cache

Writing lock file
Generating autoload files
root@tyr:/var/www/html/laravel#