Docker StorageDriver

Docker 对 container 的使用基本是建立在 LXC 基础之上，然而 LXC 存在的问题是难以通过标准化的模板去制作、重建、复制和移动 container。

在以 VM 为基础的虚拟化中，有 image 和 snapshot 可以用于 VM 的复制、重建以及移动的功能。

想要通过 container 来实现快速的大规模部署和更新，这些功能不可或缺。

在 Docker 0.7 中引入了 Storage Driver（储存驱动）, 现在已经支持 AUFS、Btrfs、Device Mapper、OverlayFS、ZFS、VFS。

一、文件系统

Union File System

简称 Union FS（联合文件系统），可以将不同物理位置的目录合并挂载(mount)到同一目录下。使其从外面看起来像一个文件系统。

例如把一张 CD/DVD 和一个硬盘目录给联合 mount 在一起，然后你就可以对这个只读的 CD/DVD 上的文件进行修改(修改的文件存于硬盘上的目录里)

Overlay2

Overlay2 是一种 Union FS

下图显示了 Docker 镜像和 Docker 容器的分层方式。镜像层是 lowerdir，容器层是 upperdir，如果镜像有多个层，则使用多个 lowerdir 目录。统一视图通过名为 merged 的目录公开，该目录实际上是容器挂载点。

在 Overlay2 文件系统中，有四个重要概念：

lowerdir：下层目录，是一个只读的目录，其中包含了基础文件系统的内容
upperdir：上层目录，是一个可写的目录，用于存储对底层目录的更改和新增文件
workdir：工作目录，用于存储挂载过程中的临时文件和元数据。它是一个必需的目录，在挂载过程中会被创建并使用，挂载完成后会被自动删除
merged：合并目录，即最终的挂载点。它是 lowerdir 和 upperdir 合并后的结果，包含了两者的文件和目录

使用 mount 命令挂载 overlay 文件系统时，需要指定这四个参数

sudo apt install -y tree

mkdir -p lowerdir lowerdir2 upperdir workdir merged
echo lowerdir > lowerdir/temp
echo lowerdir2 > lowerdir2/temp
echo upperdir > upperdir/temp
touch lowerdir/l lowerdir2/l2 upperdir/u
tree

sudo mount -t overlay overlay -o lowerdir=lowerdir:lowerdir2,upperdir=upperdir,workdir=workdir merged
tree merged
# 可以看到内容是 upperdir
cat merged/temp
# 在 merged 下新建 m，可以看到 m 在 upperdir 目录中
touch merged/m && tree

sudo umount merged

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lower 的深度限制 maxDepth：https://github.com/moby/moby/blob/master/daemon/graphdriver/overlay2/overlay.go#L73

二、Linux 系统启动

典型的 Linux 启动到运行需要两个 FS：bootfs + rootfs

bootfs（boot file system）：

主要包含 bootloader 和 kernel，bootloader 主要是引导加载 kernel，当 kernel 被加载到内存中后，bootfs 就被 umount 了，此时内存的使用权已由 bootfs 转交给 rootfs。

rootfs (root file system) ：

在 bootfs 之上。包含的就是典型 Linux 系统中的 /dev、/proc、/bin、/etc 等标准目录和文件。

由此可见对于不同的 linux 发行版，bootfs 基本是一致的，rootfs 会有差别,，因此不同的发行版可以公用共用 bootfs。如下图：

三、Docker image 结构

典型的 Linux 在启动后，首先将 rootfs 置为 readonly，进行一系列检查, 然后将其切换为 "readwrite" 供用户使用。

在 Docker 中，起初也是将 rootfs 以 readonly 方式加载并检查，然而接下来利用 union mount 将一个 readwrite 文件系统挂载在 readonly 的 rootfs 之上，并且允许再次将下层的 file system 设定为 readonly，并且向上叠加。

这样一组 readonly 和一个 writeable 的结构构成一个 container 的运行目录，每一个被称作一个 Layer。如下图：

得益于 AUFS 的特性，每一个对 readonly 层文件或目录的修改都只会存在于上层的 writeable 层中。

这样，由于不存在竞争, 多个 container 可以共享 readonly 的 layer。

所以 docker 将 readonly 的层称作 image，对于 container 而言整个 rootfs 都是 read-write 的，但事实上所有的修改都写入最上层的 writeable 层中。

image 不保存用户状态，可以用于模板、重建和复制。

某个镜像：

基于该镜像创建的容器：

上层的 image 依赖下层的 image，因此 docker 中把下层的 image 称作父 image，没有父 image 的 image 称作 base image。

因此想要从一个 image 启动一个 container，docker 会先加载其父 image 直到 base image，用户的进程运行在 writeable 的 layer 中。

所有 parent image 中的数据信息以及 ID、网络和 lxc 管理的资源限制等具体 container 的配置，构成一个 docker 概念上的 container。如下图：

Docker image 采用分层结构的好处

共享资源，节省存储空间：有多个镜像都从相同的 base 镜像构建而来，那么宿主机只需在磁盘上保存一份 base 镜像，同时内存中也只需加载一份 base 镜像，就可以为所有容器服务了。而且镜像的每一层都可以被共享。

快速部署：如果要部署多个 container，base image 可以避免多次拷贝。

内存更省：因为多个 container 共享 base image，以及 OS 的 disk 缓存机制，多个 container 中的进程命中缓存内容的几率大大增加。

升级更方便：相比于 copy-on-write 类型的文件系统，base-image 也是可以挂载为可 writeable 的，可以通过更新 base image 而一次性更新其之上的 container。

允许在不更改 base-image 的同时修改其目录中的文件，所有写操作都发生在最上层的 writeable 层中。

四、/var/lib/docker

删除 docker 数据，重启 docker，查看 /var/lib/docker 目录

sudo rm -rf /var/lib/docker/*
sudo service docker restart
sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   └── [drwx------ root root]  l
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
23 directories, 10 files

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下载镜像，/var/lib/docker/overlay2 下会新增文件

docker pull hello-world
sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   ├── [drwx--x--- root root]  56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7
│   │   ├── [drwxr-xr-x root root]  diff
│   │   └── [-rw-r--r-- root root]  link
│   └── [drwx------ root root]  l
│       └── [lrwxrwxrwx root root]  AJVRY4BDWHUFJCD4PYZX264TCD -> ../56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7/diff
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
26 directories, 11 files

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运行容器，/var/lib/docker/containers 下会新增文件

docker run hello-world
sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
│   └── [drwx--x--- root root]  fe85985b4136d2b8041c4a3f99962f599181ec1aac858d55d8f38b6d4020fc3f
│       ├── [drwx------ root root]  checkpoints
│       ├── [-rw------- root root]  config.v2.json
│       ├── [-rw-r----- root root]  fe85985b4136d2b8041c4a3f99962f599181ec1aac858d55d8f38b6d4020fc3f-json.log
│       ├── [-rw------- root root]  hostconfig.json
│       ├── [-rw-r--r-- root root]  hostname
│       ├── [-rw-r--r-- root root]  hosts
│       ├── [drwx--x--- root root]  mounts
│       ├── [-rw-r--r-- root root]  resolv.conf
│       └── [-rw-r--r-- root root]  resolv.conf.hash
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   ├── [drwx--x--- root root]  56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   └── [-rw-r--r-- root root]  link
│   ├── [drwx--x--- root root]  8607abf841bb20751aa5ac44f83692260977e2b7684776058be5512c4b151254
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  8607abf841bb20751aa5ac44f83692260977e2b7684776058be5512c4b151254-init
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   └── [drwx------ root root]  l
│       ├── [lrwxrwxrwx root root]  AAK6FNEKCJEQTTAL7R5HO24IZY -> ../8607abf841bb20751aa5ac44f83692260977e2b7684776058be5512c4b151254/diff
│       ├── [lrwxrwxrwx root root]  AJVRY4BDWHUFJCD4PYZX264TCD -> ../56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7/diff
│       └── [lrwxrwxrwx root root]  WILBHTRJ2TEEON5LGYIPSZWGPE -> ../8607abf841bb20751aa5ac44f83692260977e2b7684776058be5512c4b151254-init/diff
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
37 directories, 24 files

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删除容器，/var/lib/docker/containers 下会被删除

docker rm fe85985b4136
sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   ├── [drwx--x--- root root]  56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   └── [-rw-r--r-- root root]  link
│   └── [drwx------ root root]  l
│       └── [lrwxrwxrwx root root]  AJVRY4BDWHUFJCD4PYZX264TCD -> ../56eec5fda1c707691c75293c6cf0cc48932325b9eb5b3d49a5773175df97e4c7/diff
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
26 directories, 12 files

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删除镜像，/var/lib/docker/overlay2 下会被删除

docker rmi hello-world
sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   └── [drwx------ root root]  l
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
23 directories, 10 files

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/var/lib/docker/containers/xxx/ 下的文件

docker run --restart=always --name mysql -e MYSQL_ROOT_PASSWORD=root -e MYSQL_ROOT_HOST=% -e TZ=Asia/Shanghai -p 3306:3306 -d mysql:latest
4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01

sudo tree -augpAL 3 /var/lib/docker
[drwx--x--- root root]  /var/lib/docker
├── [drwx--x--x root root]  buildkit
│   ├── [-rw------- root root]  cache.db
│   ├── [-rw-r--r-- root root]  containerdmeta.db
│   ├── [drwxr-xr-x root root]  content
│   │   └── [drwxr-xr-x root root]  ingest
│   ├── [drwx--x--x root root]  executor
│   ├── [-rw------- root root]  history.db
│   ├── [-rw------- root root]  metadata_v2.db
│   └── [-rw------- root root]  snapshots.db
├── [drwx--x--- root root]  containers
│   └── [drwx--x--- root root]  4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01
│       ├── [-rw-r----- root root]  4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01-json.log
│       ├── [drwx------ root root]  checkpoints
│       ├── [-rw------- root root]  config.v2.json
│       ├── [-rw------- root root]  hostconfig.json
│       ├── [-rw-r--r-- root root]  hostname
│       ├── [-rw-r--r-- root root]  hosts
│       ├── [drwx--x--- root root]  mounts
│       ├── [-rw-r--r-- root root]  resolv.conf
│       └── [-rw-r--r-- root root]  resolv.conf.hash
├── [-rw------- root root]  engine-id
├── [drwx------ root root]  image
│   └── [drwx------ root root]  overlay2
│       ├── [drwx------ root root]  distribution
│       ├── [drwx------ root root]  imagedb
│       ├── [drwx------ root root]  layerdb
│       └── [-rw------- root root]  repositories.json
├── [drwxr-x--- root root]  network
│   └── [drwxr-x--- root root]  files
│       └── [-rw-r--r-- root root]  local-kv.db
├── [drwx--x--- root root]  overlay2
│   ├── [drwx--x--- root root]  01733b232b0bb9e61c3b1d91094f3cfaab0dcb393533a9561cd00838a088def0
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  034b57a460ccf5ebd5ae6fff8fc138551c569b155a4ef756a3b3adbaf449d838
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  07ba108168e36ca5f72283f46d98b29dbbf392666be45ba221ea940ca862a417
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   ├── [drwxr-xr-x root root]  merged
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62-init
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  175f333ff0891c602fecb87292686821c90ef96120df6c16a61fc438690841c9
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  19c4e084eb8c38be7f2a2754ace8d19842e1e29ca41e06ccfb0908006cc42608
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  2a7d4ecf76ef8b76b5d76676334468e9a77464441cc54ccd493624e58d60c423
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  3e135838ec038517b30bb94fd6d65ee360b63b539624ab4e7c4a1c0839108f56
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  4e12d0dcedf7c5d4ee9585364e6fb34820a2d07006216bc573ee155b7cf6435f
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  8fd048c3f3058286313a5612e4d0ce0bb4d74291c182c503346c3f2e23903979
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   └── [-rw-r--r-- root root]  link
│   ├── [drwx--x--- root root]  9891fa6521802a525785693b721672e26137007c8c9709a0dac62402ff73cd7e
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  abe0b2e6acd96862c74201805b73a7e7a60cfcff6d528b331266bc20e42fed4c
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   ├── [drwx--x--- root root]  d9ca5aa21a93f0b14edb7f3ec899f113091e4eef7ba340f3ea8a537c57491c8c
│   │   ├── [-rw------- root root]  committed
│   │   ├── [drwxr-xr-x root root]  diff
│   │   ├── [-rw-r--r-- root root]  link
│   │   ├── [-rw-rw-rw- root root]  lower
│   │   └── [drwx------ root root]  work
│   └── [drwx------ root root]  l
│       ├── [lrwxrwxrwx root root]  2AKWTAQ3QIMSCXORDH25FAS3O7 -> ../d9ca5aa21a93f0b14edb7f3ec899f113091e4eef7ba340f3ea8a537c57491c8c/diff
│       ├── [lrwxrwxrwx root root]  3Y6F3ZLWWTCB3USOSHPQD27OUS -> ../3e135838ec038517b30bb94fd6d65ee360b63b539624ab4e7c4a1c0839108f56/diff
│       ├── [lrwxrwxrwx root root]  BRPLZX3BCN57DYDEZODSRMI2HO -> ../0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62/diff
│       ├── [lrwxrwxrwx root root]  DXDRY2ODMLCDFVOR7MQA2DWH4A -> ../2a7d4ecf76ef8b76b5d76676334468e9a77464441cc54ccd493624e58d60c423/diff
│       ├── [lrwxrwxrwx root root]  G3HCZ2KFRYM7C6XBJ4UBFXPLCI -> ../175f333ff0891c602fecb87292686821c90ef96120df6c16a61fc438690841c9/diff
│       ├── [lrwxrwxrwx root root]  G4FRKLZU3DTTGK2T2T4BMUUDN3 -> ../8fd048c3f3058286313a5612e4d0ce0bb4d74291c182c503346c3f2e23903979/diff
│       ├── [lrwxrwxrwx root root]  LV5RVCKIRBRCYXVHBSVKMX2GAI -> ../4e12d0dcedf7c5d4ee9585364e6fb34820a2d07006216bc573ee155b7cf6435f/diff
│       ├── [lrwxrwxrwx root root]  ND7FYBAZM7NCLDYEPQBUWYS6TN -> ../07ba108168e36ca5f72283f46d98b29dbbf392666be45ba221ea940ca862a417/diff
│       ├── [lrwxrwxrwx root root]  POCRW5BVS5AC2QGIVIW6RMVZJE -> ../01733b232b0bb9e61c3b1d91094f3cfaab0dcb393533a9561cd00838a088def0/diff
│       ├── [lrwxrwxrwx root root]  R3DP23DR3CKYQA5SOALIW2S5US -> ../19c4e084eb8c38be7f2a2754ace8d19842e1e29ca41e06ccfb0908006cc42608/diff
│       ├── [lrwxrwxrwx root root]  RSNYJDKGE6RIFORC6BSKH6VSK2 -> ../0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62-init/diff
│       ├── [lrwxrwxrwx root root]  TCZU475LZP3EAQL5UHDASLFPPA -> ../abe0b2e6acd96862c74201805b73a7e7a60cfcff6d528b331266bc20e42fed4c/diff
│       ├── [lrwxrwxrwx root root]  WBFZLP62AQJMSJMX7Y2C4NFO4L -> ../9891fa6521802a525785693b721672e26137007c8c9709a0dac62402ff73cd7e/diff
│       └── [lrwxrwxrwx root root]  YLK4O3EQQPNR7LV25XN7BD6NRF -> ../034b57a460ccf5ebd5ae6fff8fc138551c569b155a4ef756a3b3adbaf449d838/diff
├── [drwx------ root root]  plugins
│   ├── [drwxr-xr-x root root]  storage
│   │   └── [drwxr-xr-x root root]  ingest
│   └── [drwx------ root root]  tmp
├── [drwx------ root root]  runtimes
├── [drwx------ root root]  swarm
├── [drwx------ root root]  tmp
└── [drwx-----x root root]  volumes
    ├── [drwx-----x root root]  5c76d178f23ac14b8a117b8cea75dbd46c4df2598465e29b678571213623f067
    │   └── [drwxrwxrwt 999 systemd-journal]  _data
    ├── [brw------- root root]  backingFsBlockDev
    └── [-rw------- root root]  metadata.db
84 directories, 57 files

sudo tree -augpAL 1 /var/lib/docker/overlay2/0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62/merged
[drwxr-xr-x root root]  /var/lib/docker/overlay2/0da140a0222f765e9fb73620eb93ac89b2096a35a0a5a6ae933ec0ad8e4d2e62/merged
├── [drwxr-xr-x root root]  bin
├── [drwxr-xr-x root root]  boot
├── [drwxr-xr-x root root]  dev
├── [drwxr-xr-x root root]  docker-entrypoint-initdb.d
├── [-rwxr-xr-x root root]  .dockerenv
├── [lrwxrwxrwx root root]  entrypoint.sh -> usr/local/bin/docker-entrypoint.sh
├── [drwxr-xr-x root root]  etc
├── [drwxr-xr-x root root]  home
├── [drwxr-xr-x root root]  lib
├── [drwxr-xr-x root root]  lib64
├── [drwxr-xr-x root root]  media
├── [drwxr-xr-x root root]  mnt
├── [drwxr-xr-x root root]  opt
├── [drwxr-xr-x root root]  proc
├── [drwx------ root root]  root
├── [drwxr-xr-x root root]  run
├── [drwxr-xr-x root root]  sbin
├── [drwxr-xr-x root root]  srv
├── [drwxr-xr-x root root]  sys
├── [drwxrwxrwt root root]  tmp
├── [drwxr-xr-x root root]  usr
└── [drwxr-xr-x root root]  var
21 directories, 2 files

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/config.v2.json
{
  "StreamConfig": {},
  "State": {
    "Running": true,
    "Paused": false,
    "Restarting": false,
    "OOMKilled": false,
    "RemovalInProgress": false,
    "Dead": false,
    "Pid": 4267,
    "ExitCode": 0,
    "Error": "",
    "StartedAt": "2024-01-16T02:48:15.473430682Z",
    "FinishedAt": "0001-01-01T00:00:00Z",
    "Health": null
  },
  "ID": "4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01",
  "Created": "2024-01-16T02:48:13.904966606Z",
  "Managed": false,
  "Path": "docker-entrypoint.sh",
  "Args": [
    "mysqld"
  ],
  "Config": {
    "Hostname": "4f3137783485",
    "Domainname": "",
    "User": "",
    "AttachStdin": false,
    "AttachStdout": false,
    "AttachStderr": false,
    "ExposedPorts": {
      "3306/tcp": {},
      "33060/tcp": {}
    },
    "Tty": false,
    "OpenStdin": false,
    "StdinOnce": false,
    "Env": [
      "MYSQL_ROOT_PASSWORD=root",
      "MYSQL_ROOT_HOST=%",
      "TZ=Asia/Shanghai",
      "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
      "GOSU_VERSION=1.12",
      "MYSQL_MAJOR=8.0",
      "MYSQL_VERSION=8.0.27-1debian10"
    ],
    "Cmd": [
      "mysqld"
    ],
    "Image": "mysql:latest",
    "Volumes": {
      "/var/lib/mysql": {}
    },
    "WorkingDir": "",
    "Entrypoint": [
      "docker-entrypoint.sh"
    ],
    "OnBuild": null,
    "Labels": {}
  },
  "Image": "sha256:3218b38490cec8d31976a40b92e09d61377359eab878db49f025e5d464367f3b",
  "ImageManifest": null,
  "NetworkSettings": {
    "Bridge": "",
    "SandboxID": "6c452c63f882a899a003b70dc6646936f6f80b8ec201a64170a2c10b245f5b27",
    "HairpinMode": false,
    "LinkLocalIPv6Address": "",
    "LinkLocalIPv6PrefixLen": 0,
    "Networks": {
      "bridge": {
        "IPAMConfig": null,
        "Links": null,
        "Aliases": null,
        "NetworkID": "cebf478ab715133af49740074ac02abd86cd441452887165531ba548e44a18e1",
        "EndpointID": "87c29cb428f70557cc449c155b0f5411b86a2ec1f0bacd2aa5096858bb83483d",
        "Gateway": "172.17.0.1",
        "IPAddress": "172.17.0.2",
        "IPPrefixLen": 16,
        "IPv6Gateway": "",
        "GlobalIPv6Address": "",
        "GlobalIPv6PrefixLen": 0,
        "MacAddress": "02:42:ac:11:00:02",
        "DriverOpts": null,
        "IPAMOperational": false
      }
    },
    "Service": null,
    "Ports": {
      "3306/tcp": [
        {
          "HostIp": "0.0.0.0",
          "HostPort": "3306"
        },
        {
          "HostIp": "::",
          "HostPort": "3306"
        }
      ],
      "33060/tcp": null
    },
    "SandboxKey": "/var/run/docker/netns/6c452c63f882",
    "SecondaryIPAddresses": null,
    "SecondaryIPv6Addresses": null,
    "IsAnonymousEndpoint": false,
    "HasSwarmEndpoint": false
  },
  "LogPath": "/var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01-json.log",
  "Name": "/mysql",
  "Driver": "overlay2",
  "OS": "linux",
  "RestartCount": 0,
  "HasBeenStartedBefore": true,
  "HasBeenManuallyStopped": false,
  "MountPoints": {
    "/var/lib/mysql": {
      "Source": "",
      "Destination": "/var/lib/mysql",
      "RW": true,
      "Name": "5c76d178f23ac14b8a117b8cea75dbd46c4df2598465e29b678571213623f067",
      "Driver": "local",
      "Type": "volume",
      "ID": "74b2ff7fe907e282f24823fe261085d24822698ac73224756ee4654a851af659",
      "Spec": {},
      "SkipMountpointCreation": false
    }
  },
  "SecretReferences": null,
  "ConfigReferences": null,
  "MountLabel": "",
  "ProcessLabel": "",
  "AppArmorProfile": "",
  "SeccompProfile": "",
  "NoNewPrivileges": false,
  "HostnamePath": "/var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/hostname",
  "HostsPath": "/var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/hosts",
  "ShmPath": "",
  "ResolvConfPath": "/var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/resolv.conf",
  "LocalLogCacheMeta": {
    "HaveNotifyEnabled": false
  }
}

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/hostconfig.json
{
  "Binds": null,
  "ContainerIDFile": "",
  "LogConfig": {
    "Type": "json-file",
    "Config": {}
  },
  "NetworkMode": "default",
  "PortBindings": {
    "3306/tcp": [
      {
        "HostIp": "",
        "HostPort": "3306"
      }
    ]
  },
  "RestartPolicy": {
    "Name": "always",
    "MaximumRetryCount": 0
  },
  "AutoRemove": false,
  "VolumeDriver": "",
  "VolumesFrom": null,
  "ConsoleSize": [
    35,
    122
  ],
  "CapAdd": null,
  "CapDrop": null,
  "CgroupnsMode": "host",
  "Dns": [],
  "DnsOptions": [],
  "DnsSearch": [],
  "ExtraHosts": null,
  "GroupAdd": null,
  "IpcMode": "private",
  "Cgroup": "",
  "Links": null,
  "OomScoreAdj": 0,
  "PidMode": "",
  "Privileged": false,
  "PublishAllPorts": false,
  "ReadonlyRootfs": false,
  "SecurityOpt": null,
  "UTSMode": "",
  "UsernsMode": "",
  "ShmSize": 67108864,
  "Runtime": "runc",
  "Isolation": "",
  "CpuShares": 0,
  "Memory": 0,
  "NanoCpus": 0,
  "CgroupParent": "",
  "BlkioWeight": 0,
  "BlkioWeightDevice": [],
  "BlkioDeviceReadBps": [],
  "BlkioDeviceWriteBps": [],
  "BlkioDeviceReadIOps": [],
  "BlkioDeviceWriteIOps": [],
  "CpuPeriod": 0,
  "CpuQuota": 0,
  "CpuRealtimePeriod": 0,
  "CpuRealtimeRuntime": 0,
  "CpusetCpus": "",
  "CpusetMems": "",
  "Devices": [],
  "DeviceCgroupRules": null,
  "DeviceRequests": null,
  "MemoryReservation": 0,
  "MemorySwap": 0,
  "MemorySwappiness": null,
  "OomKillDisable": false,
  "PidsLimit": null,
  "Ulimits": null,
  "CpuCount": 0,
  "CpuPercent": 0,
  "IOMaximumIOps": 0,
  "IOMaximumBandwidth": 0,
  "MaskedPaths": [
    "/proc/asound",
    "/proc/acpi",
    "/proc/kcore",
    "/proc/keys",
    "/proc/latency_stats",
    "/proc/timer_list",
    "/proc/timer_stats",
    "/proc/sched_debug",
    "/proc/scsi",
    "/sys/firmware",
    "/sys/devices/virtual/powercap"
  ],
  "ReadonlyPaths": [
    "/proc/bus",
    "/proc/fs",
    "/proc/irq",
    "/proc/sys",
    "/proc/sysrq-trigger"
  ]
}

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/hostname
4f3137783485

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/hosts
127.0.0.1       localhost
::1     localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
172.17.0.2      4f3137783485

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/resolv.conf
# This file was automatically generated by WSL. To stop automatic generation of this file, add the following entry to /etc/wsl.conf:
# [network]
# generateResolvConf = false
nameserver 172.30.160.1

sudo cat /var/lib/docker/containers/4f31377834851b73301378bc4e354237dee0cbe736311588463cab0f0fa37b01/resolv.conf.hash
sha256:1204f5aedefdf2b590fb3384410e3b44d7b54ed641d20284d4ada011f41eb072

View Code

五、Docker 镜像 commit

docker commit 提交容器副本使之成为一个新的镜像

# docker commit -m="提交的描述信息" -a="作者" 容器ID 要创建的目标镜像名:[标签名]

# 下载镜像
docker pull tomcat
# 启动镜像
docker run -d -p 8080:8080 tomcat
# 查看容器ID
docker ps -a
# 进入容器
docker exec -it a41c393cfa45 /bin/bash
# 删除 tomcat
rm -rf /usr/local/tomcat/webapps/*
# 退出容器
exit
# 生成新镜像
docker commit -m="没有 webapps 的 tomcat 镜像" -a="jhxxb" a41c393cfa45 jhxxb/tomcat-del:1.0
# 查看生成的新镜像
docker images

# 运行新镜像(需要指定版本，默认为 latest)
docker run -d -p 8080:8080 jhxxb/tomcat-del:1.0