自定义创建Docker镜像

选择基础镜像系统

首先第一步是需要拉取 centos:7作为基础镜像系统，以后所有操作均在此基础之上构建。

docker pull centos:7

确定镜像的功能

确定自己创建镜像应该提供一个怎样的功能，或者说该镜像做一件什么样的事情。

最近刚好需要对Linux服务器系统资源做一定监控，恰好发现Ganglia可以实现，于是决定将其封装成docker镜像使用。

基于选择的基础镜像创建容器

docker run -itd --name ganglia --privileged=true centos:7

Ganglia概述

Ganglia是一个开源大规模集群监控软件，用于测量数以千计的节点，适合分布式集群或并行集群监控。主要是用来监控系统性能，如：cpu 、mem、硬盘利用率，I/O负载、网络流量情况等

官网地址：http://ganglia.info/

核心组成

Ganglia由gmond、gmetad和ganglia-web三部分组成。

gmond（Ganglia Monitoring Daemon）是一种轻量级服务，安装在每台需要收集指标数据的节点主机上。使gmond，可以很容易收集很多系统指标数据，如CPU、内存、磁盘、网络和活跃进程的数据等。

gmetad（Ganglia Meta Daemon）定期检查gmonds，从那里拉取数据，整合所有信息，并将其以RRD格式存储至磁盘的服务。

gweb（Ganglia Web）Ganglia可视化工具，安装在有gmetad运行的机器上，以便读取RRD文件。 gweb是一种利用浏览器显示gmetad所存储数据的PHP前端。在Web界面中以图表方式展现集群的运行状态下收集的多种不同指标数据。

开始构建

进入容器内部进行构建操作

docker exec -it ganglia  /bin/bash

安装httpd服务与php

yum -y install httpd php

安装其他依赖

yum -y install rrdtool perl-rrdtool rrdtool-devel
yum -y install apr-devel

安装ganglia

yum -y install ganglia-gmetad
yum -y install ganglia-web
yum install -y ganglia-gmond

配置

修改配置文件 vim /etc/httpd/conf.d/ganglia.conf

Alias /ganglia /usr/share/ganglia
<Location /ganglia>
  Order deny,allow
  Deny from all
  # Allow from 127.0.0.1
  # Allow from ::1
  # Allow from .example.com
</Location>

Alias /ganglia /usr/share/ganglia
<Location /ganglia>
  # Order deny,allow
  # Deny from all
  # Allow from 127.0.0.1
  # Allow from ::1
  Allow from all
  # Allow from .example.com
  
  Require all granted
</Location>

修改配置文件vim /etc/ganglia/gmetad.conf

data_source "my cluster" localhost（本机的ip地址）

修改配置文件vim /etc/ganglia/gmond.conf

cluster {
  name = "unspecified"
  owner = "unspecified"
  latlong = "unspecified"
  url = "unspecified"
}

cluster {
  name = "my_cluster"
  owner = "unspecified"
  latlong = "unspecified"
  url = "unspecified"
}

udp_send_channel {
  #bind_hostname = yes # Highly recommended, soon to be default.
                       # This option tells gmond to use a source address
                       # that resolves to the machine's hostname.  Without
                       # this, the metrics may appear to come from any
                       # interface and the DNS names associated with
                       # those IPs will be used to create the RRDs.
  mcast_join = 239.2.11.71
  port = 8649
  ttl = 1
}

udp_send_channel {
  #bind_hostname = yes # Highly recommended, soon to be default.
                       # This option tells gmond to use a source address
                       # that resolves to the machine's hostname.  Without
                       # this, the metrics may appear to come from any
                       # interface and the DNS names associated with
                       # those IPs will be used to create the RRDs.
  # mcast_join = 239.2.11.71
  host=127.0.0.1
  port = 8649
  ttl = 1
}

udp_recv_channel {
  mcast_join = 239.2.11.71
  port = 8649
  bind = 239.2.11.71
  retry_bind = true
  # Size of the UDP buffer. If you are handling lots of metrics you really
  # should bump it up to e.g. 10MB or even higher.
  # buffer = 10485760
}


udp_recv_channel {
  # mcast_join = 239.2.11.71
  port = 8649
  bind = 127.0.0.1
  retry_bind = true
  # Size of the UDP buffer. If you are handling lots of metrics you really
  # should bump it up to e.g. 10MB or even higher.
  # buffer = 10485760
}

修改配置文件vim /etc/selinux/config

SELINUX=disabled

启动相关服务

启动服务

systemctl httpd start
systemctl gmetad start
systemctl gmond start

设置开机启动

systemctl enable start
systemctl enable start
systemctl enable start

将容器提交为镜像

基于基础容器之上进行操作完成后，将其提交为新的镜像

docker commit ganglia  ganglia:latest

使用创建的镜像创建容器

docker run -itd --name ganglia -p 8080:80 -p 8081:8649  --privileged=true ganglia:latest

访问：IP:8080/ganglia

Docker Hub

注册账号

访问: https://hub.docker.com/注册账号

登录账号

命令行登录账号

docker login -u username

Tag镜像

新建一个tag，名字必须跟注册账号一样

docker tag test:v1 username/test:v1

推送

docker push username/test:v1

拉取

docker pull username/test:v1

部署

docker run -itd 8080:80 username/test:v1