问题描述
如果我使用命令运行 Docker镜像
If I run the redis:alpine Docker image using the commmand
docker run redis:alpine
我看到一些警告：
1:C 08 May 08:29:32.308 # Warning: no config file specified, using the default config. In order to specify a config file use redis-server /path/to/redis.conf
_._
_.-``__ ''-._
_.-`` `. `_. ''-._ Redis 3.2.8 (00000000/0) 64 bit
.-`` .-```. ```\/ _.,_ ''-._
( ' , .-` | `, ) Running in standalone mode
|`-._`-...-` __...-.``-._|'` _.-'| Port: 6379
| `-._ `._ / _.-' | PID: 1
`-._ `-._ `-./ _.-' _.-'
|`-._`-._ `-.__.-' _.-'_.-'|
| `-._`-._ _.-'_.-' | http://redis.io
`-._ `-._`-.__.-'_.-' _.-'
|`-._`-._ `-.__.-' _.-'_.-'|
| `-._`-._ _.-'_.-' |
`-._ `-._`-.__.-'_.-' _.-'
`-._ `-.__.-' _.-'
`-._ _.-'
`-.__.-'
1:M 08 May 08:29:32.311 # WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128.
1:M 08 May 08:29:32.311 # Server started, Redis version 3.2.8
1:M 08 May 08:29:32.311 # 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.
1:M 08 May 08:29:32.311 # WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.
1:M 08 May 08:29:32.311 * The server is now ready to accept connections on port 6379
我尝试使用以下 Dockerfile 修复前两个警告：
I've tried to fix the first two of these warnings using the following Dockerfile:
FROM redis:alpine
COPY somaxconn /proc/sys/net/core/somaxconn
COPY sysctl.conf /etc/sysctl.conf
CMD ["redis-server", "--appendonly", "yes"]
其中我的本地文件 somaxconn 包含单个条目 511 ，而 sysctl.conf 包含以下行 vm.overcommit_memory = 1 。但是，在构建和运行容器时，我仍然收到相同的警告。
where my local file somaxconn contains the single entry 511 and sysctl.conf contains the line vm.overcommit_memory = 1. However, I still get the same warnings when I build and run the container.
如何摆脱这些警告？ （在，但此处描述的解决方案涉及修改，似乎与Rasperry Pi有关。
How can I get rid of these warnings? (There is mention of the issues in https://www.techandme.se/performance-tips-for-redis-cache-server/ but the solution described there, involving modifying rc.local, seems to pertain to Rasperry Pi).
推荐答案
处理错误的方式： / proc 是只读文件系统，可以对其进行修改，您可以在特权模式下运行Docker，而无需在操作之后进行修改。
Bad way to handle things: /proc is read-only filesystem to modify it you can run Docker in privileged mode than you can modify it after the container was started.
如果以特权模式运行容器，则可以使用以下命令禁用THP：
If running the container in privileged mode, you can disable THP using these commands:
# echo never > /sys/kernel/mm/transparent_hugepage/enabled
# echo never > /sys/kernel/mm/transparent_hugepage/defrag
正确方法：确保您运行较新版本的Docker（如果需要，请升级）。 run 子命令具有--sysctl选项：
Proper way: Ensure that you run newer versions of Docker (upgrade if needed). run subcommand has the --sysctl option:
$ docker run -ti --sysctl net.core.somaxconn=4096 --rm redis:alpine /bin/sh
root@9e850908ddb7:/# sysctl net.core.somaxconn
net.core.somaxconn = 4096
...
不幸的是： vm .overcommit_memory 当前不允许通过-sysctl 进行设置，同样适用于THP（transparent_hugepage），这是因为它们没有命名空间。因此，要在Linux主机上运行的容器中修复这些警告，可以直接在主机上更改它们。这里是相关的问题：
Unfortunately: vm.overcommit_memory is currently not allowed to be set via --sysctl paramter the same applies to THP (transparent_hugepage), this is because they are not namespaced. Thus to fix these warning in a container running on a Linux Host you can change them directly on host. Here the related Issues:
- #19
- #55
正确方法方法不需要特权模式
这篇关于运行redis：Alpine Docker镜像时如何修复警告的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！