Docker入門學習序列（一）

第2章 搭建你的第一個Docker應用棧

QUESTION 1:docker hub pull鏡像失敗

[root@nxl-test nxl]# docker pull ubuntu
Using default tag: latest
Error response from daemon: Get https://registry-1.docker.io/v2/library/ubuntu/manifests/latest: Get https://auth.docker.io/token?scope=repository%3Alibrary%2Fubuntu%3Apull&service=registry.docker.io: net/http: TLS handshake timeout

主要原因：

• 解析ip不可用
• dns域名沒有解析
• 訪問docker hub網速不好

Solution 1：多pull幾次；

Solution 2：解析Docker Hub IP，手動修改修改docker.io的域名。

1. 下載一個big工具

yum install bind-utils

安裝完畢後，輸入命令``，顯示很多可用ip

[root@nxl-test nxl]# dig @114.114.114.114 registry-1.docker.io

; <<>> DiG 9.11.4-P2-RedHat-9.11.4-9.P2.el7 <<>> @114.114.114.114 registry-1.docker.io
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 57701
;; flags: qr rd ra; QUERY: 1, ANSWER: 8, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 512
;; QUESTION SECTION:
;registry-1.docker.io.		IN	A

;; ANSWER SECTION:
registry-1.docker.io.	36	IN	A	100.24.246.89
registry-1.docker.io.	36	IN	A	54.152.200.115
registry-1.docker.io.	36	IN	A	3.221.133.86
registry-1.docker.io.	36	IN	A	52.87.94.70
registry-1.docker.io.	36	IN	A	3.224.11.4
registry-1.docker.io.	36	IN	A	3.210.179.11
registry-1.docker.io.	36	IN	A	54.174.39.59
registry-1.docker.io.	36	IN	A	54.210.105.17

;; Query time: 30 msec
;; SERVER: 114.114.114.114#53(114.114.114.114)
;; WHEN: 六 2月 29 15:55:34 CST 2020
;; MSG SIZE  rcvd: 177

從中任意選一個ip,這裏我們選擇52.87.94.70，
然後在/etc/hosts目錄下去修改docker.io的域名解析到其它可用IP
命令如下:

vi /etc/host 
34.199.77.19 registry-1.docker.io

保存後重啓docker.

systemctl restart docker

Solution 3 (dial tcp: lookup auth.docker.io: no such host)

通過命令去我們linux的dns配置 文件

vi /etc/resolv.conf
nameserver 8.8.4.4  //新增谷歌的dns域名解析地址:
nameserver localdomain  //再配置一個默認解析地址(如果有請忽略)

重啓容器

systemctl restart docker

Solution 4 換成本地源

QUESTION 2：exit退出，同時關閉了正在運行的容器

Description：

• 創建容器，進入容器，exit退出，容器關閉；
• docker attach [containers]， exit退出，容器關閉；

[root@nxl-test nxl]# docker run -it --name redis-master redis /bin/bash
root@f1d18470a9fa:/data# exit
[root@nxl-test nxl]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED              STATUS                      PORTS               NAMES
8b7c91dbfbdf        redis                 "docker-entrypoint.s…"   11 seconds ago       Created                     6379/tcp            redis-slave1
f1d18470a9fa        redis                 "docker-entrypoint.s…"   About a minute ago   Exited (0) 41 seconds ago                       redis-master

Solution 1：退出容器時，按住：Ctrl+P+Q退出容器，容器正常在後臺運行

root@f1d18470a9fa:/data# read escape sequence
[root@nxl-test nxl]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                   PORTS               NAMES
8b7c91dbfbdf        redis                 "docker-entrypoint.s…"   17 minutes ago      Created                  6379/tcp            redis-slave1
f1d18470a9fa        redis                 "docker-entrypoint.s…"   19 minutes ago      Up 8 minutes             6379/tcp            redis-master
7dc3c5282b45        portainer/portainer   "/portainer"             2 days ago          Exited (2) 6 hours ago                       happy_moore

Solution 2：創建容器時加-d，容器後臺運行

[root@nxl-test nxl]# docker run -it -d --name redis-master1 redis /bin/bash
1c5d1ab99df3cf9957cd8b62668651d677048db30aa498a700a864571c02aa0d

Solution 3：進入正在運行的容器，用 docker exec [containers]

[root@nxl-test nxl]# docker exec -it redis-master1 /bin/bash
root@1c5d1ab99df3:/data# exit
exit
[root@nxl-test nxl]# docker ps -a
CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS                   PORTS               NAMES
1c5d1ab99df3        redis                 "docker-entrypoint.s…"   4 minutes ago       Up 4 minutes             6379/tcp            redis-master1
f1d18470a9fa        redis                 "docker-entrypoint.s…"   32 minutes ago      Up 21 minutes            6379/tcp            redis-master
7dc3c5282b45        portainer/portainer   "/portainer"             2 days ago          Exited (2) 7 hours ago

QUESTION 3：docker inspect --format “{{ .Volume }}” f1d1 報錯

Description

[root@nxl-test nxl]# docker inspect --format "{{ .Volumes }}" f1d18470a9fa
Template parsing error: template: :1:3: executing "" at <.volumes>: map has

使用grep

[root@nxl-test ~]# docker inspect f1d18470a9fa | grep Mounts -A 10
        "Mounts": [
            {
                "Type": "volume",
                "Name": "ebf32045389654a6fabe6b9c3dd81abd552cac849dffc529738c63a409edf796",
                "Source": "/var/lib/docker/volumes/ebf32045389654a6fabe6b9c3dd81abd552cac849dffc529738c63a409edf796/_data",
                "Destination": "/data",
                "Driver": "local",
                "Mode": "",
                "RW": true,
                "Propagation": ""
            }

QUESTION 4：redis 主從庫數據不一致，主庫輸入，從庫get 返回 nil

redis.conf配置文件地址

Description

redis-master info replication

127.0.0.1:6379> info replication
# Replication
role:master
connected_slaves:0 //沒有slave

redis-slave info replication

127.0.0.1:6379> info replication
# Replication
role:slave
master_host:master
master_port:6379
master_link_status:down  //和主節點連接不成功
...

Solution 1：關閉機器防火牆或者在防火牆裏添加端口6379/tcp

[root@nxl-test ~]# firewall-cmd --add-port=6379/tcp   
FirewallD is not running   //說明防火牆本身是關閉的，排除防火牆問題。
[root@nxl-test ~]# yum install iptables-services  //順手安裝iptables 工具
[root@nxl-test ~]# service iptables status
Redirecting to /bin/systemctl status iptables.service
● iptables.service - IPv4 firewall with iptables
   Loaded: loaded (/usr/lib/systemd/system/iptables.service; disabled; vendor preset: disabled)
   Active: inactive (dead)

Solution 2：master節點bind 127.0.0.1註釋掉，驗證我這邊不行。

Solution 3：master節點改成bind 0.0.0.0，成功。

將master 節點redis.conf文件中，bind 127.0.0.1 改成 bind 0.0.0.0, kill -9原master redis-server進程，重新開啓redis-server redis.conf成功。

查看進程號：ps -ef | grep redis

// master node
127.0.0.1:6379> info replication
# Replication
role:master
connected_slaves:2
slave0:ip=172.18.0.3,port=6379,state=online,offset=112,lag=0
slave1:ip=172.18.0.4,port=6379,state=online,offset=112,lag=0
//slave node
127.0.0.1:6379> info replication
# Replication
role:slave
master_host:master
master_port:6379
master_link_status:up
...

設置爲 0.0.0.0 表示都可以訪問
如果是127.0.0.1 表示localhost訪問
如果不設置從就沒有訪問主的權限

QUESTION 3：yum 安裝時出現：Loading mirror speeds from cached hostfile

Description

[root@nxl-test ~]# yum install -y install iputils-ping
已加載插件：fastestmirror
Loading mirror speeds from cached hostfile
沒有可用軟件包 install。
沒有可用軟件包 iputils-ping。

QUESTION 3：Django的BUG：ImportError: cannot import name ‘patterns’

Description

在學習Docker容器與容器雲第2版時出現的BUG：
第二章，搭建第一個Hello World程序，運行：
python manage.py makemigrations
出現
ImportError: cannot import name 'patterns'

Solution:https://blog.csdn.net/RivenDong/article/details/101626955