Docker數據管理

容器中管理數據主要有兩種方式:linux

  1. 數據卷(Data Volumes)
  2. 數據卷容器(Data Volume Containers)

數據卷

數據卷是一個可供容器使用的特殊目錄,它繞過文件系統,能夠提供不少有用的特性:docker

  • 數據卷能夠在容器之間共享和重用;
  • 對數據卷的修改會立馬有效;
  • 對數據卷的更新,不會影響鏡像;
  • 卷會一直存在,直到沒有容器使用。

數據卷的使用,相似於Linux下對目錄或文件進行mount操做。centos

掛載本地的目錄到容器裏

[root@localhost ~]# docker images
REPOSITORY                   TAG                 IMAGE ID            CREATED             VIRTUAL SIZE
registry                     latest              5c929a8b587a        29 hours ago        33.27 MB
genesis_centos               latest              85bc3a58f134        5 days ago          277.6 MB
192.168.1.179:5000/busybox   latest              9967c5ad88de        12 days ago         1.093 MB
busybox                      latest              9967c5ad88de        12 days ago         1.093 MB
centos-6-x86                 latest              8fca9486a39b        13 days ago         341.3 MB
centos_with_net              latest              3e8ea8607f08        4 weeks ago         294.9 MB
centos                       latest              9baab0af79c4        6 weeks ago         196.7 MB
[root@localhost ~]# ls /data/
ls: 沒法訪問/data/: 沒有那個文件或目錄
[root@localhost ~]# mkdir /data/
[root@localhost ~]# docker run -itd -v /data/:/data1 centos bash
096460f831bfd72b2efc6ba6b7e7bb060152afa49506ef26e0fa3cb03974f8d5
  • -v 用來指定掛載目錄
  • 「:」前面的/data/爲本地目錄
  • 「:」後面的/data1/爲容器裏的目錄
[root@localhost ~]# touch /data/1.txt
[root@localhost ~]# echo "test" > /data/1.txt
[root@localhost ~]# docker exec -it 09646 bash
[root@096460f831bf /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-096460f831bfd72b2efc6ba6b7e7bb060152afa49506ef26e0fa3cb03974f8d5  9.8G  231M  9.0G   3% / tmpfs 936M 0 936M 0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data1 [root@096460f831bf /]# ls /data1/
1.txt
[root@096460f831bf /]# cat /data1/1.txt
test
[root@096460f831bf /]# touch /data1/2.txt
[root@096460f831bf /]# exit
exit
[root@localhost ~]# ls /data/
1.txt  2.txt

無論是把容器停掉、仍是刪除,數據仍是存在的ruby

[root@localhost ~]# docker stop 09646
09646
[root@localhost ~]# ls /data/
1.txt  2.txt
[root@localhost ~]# docker rm 09646
09646
[root@localhost ~]# ls /data/
1.txt  2.txt

掛載數據卷

[root@localhost ~]# docker run -itd -v /data/:/data1 centos bash
e136b27a8e177d878e76c60aafade32df947a60f77b3f95dcaf0680b7ffbc6e8
[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
e136b27a8e17        centos              "bash"              14 seconds ago      Up 13 seconds                           tender_euclid

其實掛載目錄的時候能夠指定容器name,若是不指定就隨機定義了。好比上面咱們沒有指定它,就生成了一個名字爲tender_euclid,這個名字可使用命令 docker ps 看最右側一列。bash

[root@localhost ~]# docker run -itd --volumes-from tender_euclid centos bash
3222c7c5c45687e0650b699a9291bc50ecc85030acf8f388c1c6a50b0dc67164

這樣咱們使用centos鏡像建立了新的容器,而且使用了tender_euclid容器的數據卷。app

[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
3222c7c5c456        centos              "bash"              26 seconds ago      Up 25 seconds                           sick_albattani
e136b27a8e17        centos              "bash"              6 minutes ago       Up 6 minutes                            tender_euclid
[root@localhost ~]# docker exec -it 3222 bash
[root@3222c7c5c456 /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-3222c7c5c45687e0650b699a9291bc50ecc85030acf8f388c1c6a50b0dc67164  9.8G  231M  9.0G   3% / tmpfs 936M 0 936M 0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data1 [root@3222c7c5c456 /]# ls /data1/
1.txt  2.txt
[root@3222c7c5c456 /]# touch /data1/3.txt
[root@3222c7c5c456 /]# ls -l /data1/
total 4
-rw-r--r--. 1 root root 5 Oct 20 05:53 1.txt
-rw-r--r--. 1 root root 0 Oct 20 05:59 2.txt
-rw-r--r--. 1 root root 0 Oct 20 06:31 3.txt
[root@3222c7c5c456 /]# exit
exit
[root@localhost ~]# ls /data/
1.txt  2.txt  3.txt

數據卷容器

定義數據卷容器

有時候,咱們須要多個容器之間相互共享數據,相似於linux裏面的NFS。因此就能夠搭建一個專門的數據卷容器,而後其餘容器直接掛載該數據卷。post

首先創建數據卷容器spa

[root@localhost ~]# docker run -itd -v /data/ --name cent_testv centos bash
fb45150dbc218e71ff07eca44be3603e004e01b94effcca14c2bd8b3a998f096
  • 注意:這裏的/data/是容器的/data目錄,並不是本地的/data/目錄
[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
fb45150dbc21        centos              "bash"              8 minutes ago       Up 8 minutes                            cent_testv
3222c7c5c456        centos              "bash"              52 minutes ago      Up 52 minutes                           sick_albattani
e136b27a8e17        centos              "bash"              58 minutes ago      Up 58 minutes                           tender_euclid
[root@localhost ~]# docker exec -it cent_testv bash
[root@fb45150dbc21 /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-fb45150dbc218e71ff07eca44be3603e004e01b94effcca14c2bd8b3a998f096 9.8G 231M 9.0G 3% /
tmpfs                                                                                              936M     0  936M   0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data
[root@fb45150dbc21 /]# ls /data/
[root@fb45150dbc21 /]# exit
exit
[root@localhost ~]# ls /data/
1.txt  2.txt  3.txt

其餘容器掛載該數據卷3d

[root@localhost ~]# docker run -itd --volumes-from cent_testv centos bash
0a80861145c9a2627618a78db2b7225eba64137d4664d3706e02c1c623cde5e3
  • 注意:使用–volumes-from參數所掛載數據卷的容器自身並不須要保持在運行狀態
[root@localhost ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
0a80861145c9        centos              "bash"              3 seconds ago       Up 2 seconds                            mad_carson
fb45150dbc21        centos              "bash"              14 minutes ago      Up 14 minutes                           cent_testv
3222c7c5c456        centos              "bash"              58 minutes ago      Up 58 minutes                           sick_albattani
e136b27a8e17        centos              "bash"              About an hour ago   Up About an hour                        tender_euclid
[root@localhost ~]# docker exec -it 0a8086 bash
[root@0a80861145c9 /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-0a80861145c9a2627618a78db2b7225eba64137d4664d3706e02c1c623cde5e3 9.8G 231M 9.0G 3% /
tmpfs                                                                                              936M     0  936M   0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data
[root@0a80861145c9 /]# touch /data/fight.txt
[root@0a80861145c9 /]# exit
exit
[root@localhost ~]# docker exec -it cent_testv bash
[root@fb45150dbc21 /]# ls /data/
fight.txt
[root@fb45150dbc21 /]# exit
exit

利用數據卷容器遷移數據

數據卷的備份

[root@localhost ~]# docker run -itd --volumes-from cent_testv -v /vol_data_backup/:/backup centos bash
4f5bf6f33f2c78197e54e5145824e98bf89d802376e83019c2913b336fbd9d20

首先咱們須要使用cent_testv數據卷新開一個容器,同時咱們還須要把本地的/vol_data_backup/目錄掛載到該容器的/backup下,這樣在容器中/backup目錄裏面新建的文件咱們就能夠直接在/vol_data_backup/目錄中看到了。 而後再把/data/目錄下面的文件打包到成data.tar文件放到/backup目錄下面。code

[root@localhost ~]# docker exec -it 4f5bf bash
[root@4f5bf6f33f2c /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-4f5bf6f33f2c78197e54e5145824e98bf89d802376e83019c2913b336fbd9d20  9.8G  231M  9.0G   3% /
tmpfs                                                                                              936M     0  936M   0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data
[root@4f5bf6f33f2c /]# ls /backup/
[root@4f5bf6f33f2c /]# ls /data/
fight.txt

[root@4f5bf6f33f2c /]# tar cvf /backup/data.tar /data/
tar: Removing leading `/' from member names
/data/
/data/fight.txt
[root@4f5bf6f33f2c /]# exit
exit
[root@localhost ~]# ls /vol_data_backup/
data.tar

恢復

先新建一個數據卷容器,再建一個新的容器並掛載該數據卷容器,而後再把tar包解包。

[root@localhost ~]# docker run -itd -v /data --name cent_testv2 centos bash
4cd696928bbe6e0aec9bf8b6856323d7228eb65006b21849eff9f0d41dcea90f
[root@localhost ~]# docker run -itd --volumes-from cent_testv2 -v /vol_data_backup/:/backup centos
7169e8be6d3e5836b626806696046195ed600a1f95b308495e90e6c7b15170d5
[root@localhost ~]# docker exec -it 7169 bash
[root@7169e8be6d3e /]# df -h
Filesystem                                                                                         Size  Used Avail Use% Mounted on
/dev/mapper/docker-253:0-1447735-7169e8be6d3e5836b626806696046195ed600a1f95b308495e90e6c7b15170d5  9.8G  231M  9.0G   3% / tmpfs 936M 0 936M 0% /dev
shm                                                                                                 64M     0   64M   0% /dev/shm
/dev/mapper/VolGroup-lv_root                                                                        35G  6.0G   28G  18% /data [root@7169e8be6d3e /]# ls /backup/
data.tar
[root@7169e8be6d3e /]# mv /backup/data.tar .
[root@7169e8be6d3e /]# ls
anaconda-post.log  bin   data.tar  etc   lib    lost+found  mnt  proc  run   srv  tmp  var
backup             data  dev       home  lib64  media       opt  root  sbin  sys  usr
[root@7169e8be6d3e /]# tar xvf data.tar
data/
data/fight.txt
[root@7169e8be6d3e /]# ls /data/
fight.txt
[root@7169e8be6d3e /]# exit
exit
[root@localhost ~]# ls /vol_data_backup/
[root@localhost ~]#
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