无需重新启动守护程序即可重新加载 docker 日志记录配置

Question

我有一些正在运行的 kubernetes 集群，它可能会产生大量日志。Kubernetes 运行在 docker 之上，所以我想我需要配置 dockerd 来推出日志。

我找到了一些 dockerd 日志驱动程序的设置：

{
  "log-driver": "json-file",
  "log-opts": {
    "max-size": "10k",
    "max-file": "2"
  }
}

在 docker 服务重启的情况下，更改成功应用。

du /var/lib/docker/containers/container_hash/container_hash* -h

显示按适当大小分块的日志文件。

但我不想重新启动守护进程，所以尝试重新加载配置：

sudo kill -SIGHUP $(pidof dockerd)

在系统日志中我发现：

Mar 12 15:38:16 kso-gl dockerd[5331]: time="2018-03-12T15:38:16.446894155+02:00" level=info msg="Got signal to reload configuration, reloading fr
om: /etc/docker/daemon.json"

所以，我假设配置已重新加载。不幸的是它没有效果。即使是新的容器。看起来与日志驱动程序相关的子系统忽略了配置重新加载。

Answer 1

遗憾的是，似乎配置重新加载 SIGHUP 功能不支持所有配置选项。

https://docs.docker.com/v17.09/engine/reference/commandline/dockerd/#miscellaneous-options 上的文档（请参阅“配置重新加载行为”部分）告诉我们可以重新加载的唯一支持的配置选项这种方式是：

The list of currently supported options that can be reconfigured is this:

debug: it changes the daemon to debug mode when set to true.
cluster-store: it reloads the discovery store with the new address.
cluster-store-opts: it uses the new options to reload the discovery store.
cluster-advertise: it modifies the address advertised after reloading.
labels: it replaces the daemon labels with a new set of labels.
live-restore: Enables keeping containers alive during daemon downtime.
max-concurrent-downloads: it updates the max concurrent downloads for each pull.
max-concurrent-uploads: it updates the max concurrent uploads for each push.
default-runtime: it updates the runtime to be used if not is specified at container creation. It defaults to “default” which is the runtime shipped with the official docker packages.
runtimes: it updates the list of available OCI runtimes that can be used to run containers
authorization-plugin: specifies the authorization plugins to use.
allow-nondistributable-artifacts: Replaces the set of registries to which the daemon will push nondistributable artifacts with a new set of registries.
insecure-registries: it replaces the daemon insecure registries with a new set of insecure registries. If some existing insecure registries in daemon’s configuration are not in newly reloaded insecure resgitries, these existing ones will be removed from daemon’s config.
registry-mirrors: it replaces the daemon registry mirrors with a new set of registry mirrors. If some existing registry mirrors in daemon’s configuration are not in newly reloaded registry mirrors, these existing ones will be removed from daemon’s config.

如您所见，其中不包括log-driver或log-opts配置参数。

目前，我不知道有什么方法可以在不重启的情况下重新加载日志记录配置。