我已经在新的CentOS 7盒子上安装了redis，但无法使用systemctl启动它。
它是这样安装的：
rpm -i http://dl.fedoraproject.org/pub/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm yum install redis 试图像这样启动它似乎默默无闻（没有输出）：
systemctl start redis-server # also tried redis-server.service
以下是尝试连接时发生的情况：
redis-cli Could not connect to Redis at 127.0.0.1:6379: Connection refused not connected>
但手动启动它的作品：
[root@redis ~]# redis-server /etc/redis.conf [root@redis ~]# redis-cli 127.0.0.1:6379>
任何人都知道什么是错的，或者如何debugging呢？
更新： /var/log/redis/redis.log输出如下。 顺便说一句，这是一个512MB的RAM VPS。
[1972] 29 Jul 18:52:16.258 # You requested maxclients of 10000 requiring at least 10032 max file descriptors. [1972] 29 Jul 18:52:16.258 # Redis can't set maximum open files to 10032 because of OS error: Operation not permitted. [1972] 29 Jul 18:52:16.258 # Current maximum open files is 1024. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'. _._ _.-``__ ''-._ _.-`` `. `_. ''-._ Redis 2.8.13 (00000000/0) 64 bit .-`` .-```. ```\/ _.,_ ''-._ ( ' , .-` | `, ) Running in stand alone mode |`-._`-...-` __...-.``-._|'` _.-'| Port: 6379 | `-._ `._ / _.-' | PID: 1972 `-._ `-._ `-./ _.-' _.-' |`-._`-._ `-.__.-' _.-'_.-'| | `-._`-._ _.-'_.-' | http://redis.io `-._ `-._`-.__.-'_.-' _.-' |`-._`-._ `-.__.-' _.-'_.-'| | `-._`-._ _.-'_.-' | `-._ `-._`-.__.-'_.-' _.-' `-._ `-.__.-' _.-' `-._ _.-' `-.__.-' [1972] 29 Jul 18:52:16.259 # Server started, Redis version 2.8.13 [1972] 29 Jul 18:52:16.259 # WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add 'vm.overcommit_memory = 1' to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect. [1972] 29 Jul 18:52:16.260 * DB loaded from disk: 0.001 seconds [1972] 29 Jul 18:52:16.260 * The server is now ready to accept connections on port 6379 [1972] 29 Jul 18:52:16.265 # User requested shutdown... [1972] 29 Jul 18:52:16.265 * Saving the final RDB snapshot before exiting. [1972] 29 Jul 18:52:16.267 * DB saved on disk [1972] 29 Jul 18:52:16.267 * Removing the pid file. [1972] 29 Jul 18:52:16.267 # Redis is now ready to exit, bye bye...
和状态：
[root@redis ~]# systemctl status redis-server redis-server.service - Redis persistent key-value database Loaded: loaded (/usr/lib/systemd/system/redis-server.service; disabled) Active: inactive (dead) Jul 29 18:52:16 redis systemd[1]: Starting Redis persistent key-value database... Jul 29 18:52:16 redis systemd[1]: Started Redis persistent key-value database.
最后，修正它。 Systemd要求redis运行非守护进程，所以configuration需要更改：
# /etc/redis.conf daemonize yes # << comment this out