Dockerfile image making practice

Posted by keigowei on Fri, 24 Apr 2020 17:20:41 +0200

If you don't know what Dockerfile is, you can check my previous blog:
https://blog.51cto.com/14557905/2489466
Dockerfile image production practice
Three steps for Dockerfile to create image

1, Making sshd image
1. Write Dockerfile file

[root@docker sshd]# vim Dockerfile
#base image 
FROM centos:7
#User information
MAINTAINER this is sshd project
#Based on basic image system update, software installation
RUN yum -y update
RUN yum -y install openssh* net-tools lsof telnet passwd
#Set user password
RUN echo '123456' | passwd --stdin root
#Turn off PAM certification
RUN sed -i 's/UsePAM yes/UsePAM no/g' /etc/ssh/sshd_config
#Add asymmetric key
RUN ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
#Close pam session module
RUN sed -i '/^session\s\+requied\s\+pam_loginuid.so/s/^/#/' /etc/pam.d/sshd
#Create ssh working directory and set permissions
RUN mkdir -p /root/.ssh && chown root.root /root && chmod 700 /root/.ssh
#Set port number
EXPOSE 22
#Take action when starting container
CMD ["/usr/sbin/sshd","-D"]

2. Create image

[root@docker sshd]# docker build -t sshd:new .
[root@docker sshd]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
sshd                new                 43e794cf8abd        19 seconds ago      585MB
centos              7                   5e35e350aded        5 months ago        203MB

3. Create container validation

[root@docker sshd]# docker run -d -P sshd:new 
[root@docker sshd]# docker ps -a
CONTAINER ID        IMAGE               COMMAND               CREATED             STATUS              PORTS                   NAMES
99cd8001ff28        sshd:new            "/usr/sbin/sshd -D"   4 seconds ago       Up 3 seconds        0.0.0.0:32768->22/tcp   compassionate_beaver
#The host uses ssh to log in the container
[root@docker sshd]# ssh localhost -p 32768
The authenticity of host '[localhost]:32768 ([::1]:32768)' can't be established.
RSA key fingerprint is SHA256:DND5bet+Io1sjjiKpNS6BvoeJC+YD07ejhRcp7s8VtQ.
RSA key fingerprint is MD5:a4:0e:3d:5a:18:1e:b2:17:85:f6:df:a5:ce:ab:d2:82.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '[localhost]:32768' (RSA) to the list of known hosts.
root@localhost's password: 
[root@2a9bcdd7681f ~]#

2, Create systemctl image
After creating the sshd image, you cannot use the systemctl status sshd command to view the ssh status. You can add the systemctl function according to the sshd image
1. Write Dockerfile file

[root@docker systemctl]# vim Dockerfile
#base image 
FROM sshd:new
#Setting environment variables
ENV container docker
#Enter the specified directory, use for loop to traverse all files under the directory and delete the specified files
RUN (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == \
systemd-tmpfiles-setup.service ] || rm -f $i; done); \
rm -f /lib/systemd/system/multi-user.target.wants/*; \
rm -f /etc/systemd/system/*.wants/*; \
rm -f /lib/systemd/system/local-fs.target.wants/*; \
rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
rm -f /lib/systemd/system/basic.target.wants/*; \
rm -f /lib/systemd/system/anaconda.target.wants/*;
#Mount the cgrups volume of the host to execute the container
VOLUME ["/sys/fs/cgroup"]
#Execute initialization command
CMD ["/usr/sbin/init"]

2. Create image

[root@docker systemctl]# docker build -t systemctl:new .
[root@docker systemctl]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
systemctl           new                 b029bbbd8a6b        9 minutes ago       585MB
sshd                new                 4b69240205be        33 minutes ago      585MB
centos              7                   5e35e350aded        5 months ago        203MB

3. Create container validation

[root@docker systemctl]# docker run --privileged -it -v /sys/fs/cgroup/:/sys/fs/cgroup:ro systemctl:new /sbin/init
[root@docker ~]# docker ps -a
CONTAINER ID        IMAGE               COMMAND               CREATED             STATUS              PORTS                   NAMES
d98f478ccaf3        systemctl:new       "/sbin/init"      2 minutes ago       Up 2 minutes        22/tcp                  practical_fermat
[root@docker ~]# docker exec -it d98f478ccaf3 bash
#Normal use of systemctl command to view
[root@d98f478ccaf3 /]# systemctl status sshd
‚óŹ sshd.service - OpenSSH server daemon
   Loaded: loaded (/usr/lib/systemd/system/sshd.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:sshd(8)
           man:sshd_config(5)

3, Create nginx image (compiled manually)
1. Write dockerfile file

[root@docker nginx]# vim Dockerfile
  #base image 
FROM centos:7
  #User information
MAINTAINER This is Nginx test
  #Based on basic image system update, environment package installation
RUN yum -y update
RUN yum -y install make gcc gcc-c++ pcre-devel zlib-devel tar
  #Creating nginx users
RUN useradd -M -s /sbin/nologin nginx
  #Upload nginx package and decompress it (you can decompress the uploaded package directly by using ADD option)
COPY nginx-1.12.2.tar.gz /opt/
RUN tar zxvf /opt/nginx-1.12.2.tar.gz -C /opt
  #Start compiling and installing nginx in the specified directory
WORKDIR /opt/nginx-1.12.2/
RUN ./configure --prefix=/usr/local/nginx --user=nginx --group=nginx --with-http_stub_status_module
RUN make && make install
  #Setting environment variables
ENV PATH /usr/local/nginx/sbin:$PATH
  #Specify port
EXPOSE 80
#Modify the Nginx configuration file to start in a non daemon mode
RUN echo "daemon off;" >> /usr/local/nginx/conf/nginx.conf
#Add running script, set permissions
ADD run.sh /run.sh
RUN chmod 755 /run.sh
#Specifies the script to execute when the container is opened
CMD ["/run.sh"]

2. Write run.sh startup script and upload nginx package

[root@docker nginx]# vim run.sh
#!/bin/bash
/usr/local/nginx/sbin/nginx

3. Create image

[root@docker nginx]# docker build -t nginx:new .
[root@docker nginx]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
nginx               new                 24b44e614799        14 seconds ago      585MB
centos              7                   5e35e350aded        5 months ago        203MB

4. Create container validation

#Create container and randomly generate mapping port
[root@docker nginx]# docker run -d -P nginx:new 
#View container and mapped port number
[root@docker nginx]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                   NAMES
b51160232ad8        nginx:new           "/run.sh"           4 seconds ago       Up 3 seconds        0.0.0.0:32775->80/tcp   sad_rhodes

Access authentication in browser

4, Create Tomcat image
1. Write Dockerfile file

[root@docker tomcat]# vim Dockerfile 
#base image 
FROM centos:7
#User information
MAINTAINER Tomcat test
#Update system based on basic image
RUN yum -y update
#Install java environment package
COPY jdk-8u201-linux-x64.rpm /opt/
RUN rpm -ivh /opt/jdk-8u201-linux-x64.rpm
#Setting environment variables of java
ENV JAVA_HOME /usr/java/jdk1.8.0_201-amd64
ENV CLASSPATH $JAVA_HOME/lib/tools.jar:$JAVA_HOME/lib/dt.jar
ENV PATH $JAVA_HOME/bin:$PATH
#Install tomcat
ADD apache-tomcat-9.0.16.tar.gz /opt/tomcat
RUN mv /opt/tomcat/apache-tomcat-9.0.16/ /usr/local/tomcat
#Specify port
EXPOSE 8080
#Specifies the operation when the container starts, where the ENTERYPOINT can also be replaced with CMD
ENTRYPOINT ["/usr/local/tomcat/bin/catalina.sh","run"]

2. Upload the required installation package to the current directory

[root@docker tomcat]# ls
apache-tomcat-9.0.16.tar.gz  Dockerfile  jdk-8u201-linux-x64.rpm

3. Image production

[root@docker tomcat]# docker build -t tomcat:new .
[root@docker tomcat]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
tomcat              new                 8b86bbc483a4        3 minutes ago       981MB
centos              7                   5e35e350aded        5 months ago        203MB

4. Create container validation

[root@docker tomcat]# docker run -d -P tomcat:new 
[root@docker tomcat]# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                     NAMES
3d94d5eddca0        tomcat:new          "/usr/local/tomcat/b..."   3 seconds ago       Up 2 seconds        0.0.0.0:32776->8080/tcp   optimistic_dubinsk

5. Access authentication on Browser

Create mysql image
1. Write Dockerfile file

[root@docker mysql]# vim Dockerfile
#base image 
FROM centos:7
#User information
MAINTAINER This is MySQL Project
#Based on basic image system update and environment package installation
RUN yum -y update
RUN yum install -y ncurses-devel autoconf cmake gcc gcc-c++ make pcre-devel expat-devel pcre
#Add mysql-5.6 installation package
ADD mysql-5.6.26.tar.gz /opt
#Enter the specified directory to compile and install mysql
WORKDIR /opt/mysql-5.6.26
RUN cmake \
-DCMAKE_INSTALL_PREFIX=/usr/local/mysql \
-DDEFAULT_CHARSET=utf8 \
-DDEFAULT_COLLATION=utf8_general_ci \
-DEXTRA_CHARSETS=all \
-DSYSCONFIDIR=/etc \
-DMYSQL_DATADIR=/home/mysql/ \
-DMYSQL_UNIX_ADDR=/home/mysql/mysql.sock
RUN make && make install
#Add mysql profile
RUN rm -f /etc/my.cnf
RUN cp /opt/mysql-5.6.26/support-files/my-default.cnf /etc/my.cnf
#Add mysql startup script and set permissions
RUN cp /opt/mysql-5.6.26/support-files/mysql.server /etc/init.d/mysqld
RUN chmod 755 /etc/init.d/mysqld
#Setting environment variables
ENV PATH $PATH:/usr/local/mysql/bin
#Create mysql user and change the permission of mysql installation directory
RUN useradd -s /sbin/nologin mysql
RUN chown -R mysql:mysql /usr/local/mysql/
#Initialize database
RUN /usr/local/mysql/scripts/mysql_install_db \
--user=mysql \
--ldata=/var/lib/mysql \
--basedir=/usr/local/mysql \
--datadir=/home/mysql
#Establish the soft connection of the sock file and change the startup script file
RUN ln -s /var/lib/mysql/mysql.sock  /home/mysql/mysql.sock
RUN sed -i '46 s/basedir=/basedir=\/usr\/local\/mysql/' /etc/init.d/mysqld
RUN sed -i '47 s/datadir=/datadir=\/home\/mysql/' /etc/init.d/mysqld
#Specify port
EXPOSE 3306
#Specifies the action when the container starts
CMD ["mysqld_safe"]

2. Upload the installation package to the current directory

[root@docker mysql]# ls
Dockerfile  mysql-5.7.26.tar.gz

3. Create image

[root@docker mysql]# docker build -t mysqld:new .
[root@docker mysql]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
mysqld              new                 9b2703bd15c0        54 minutes ago      5.11GB
centos              7                   5e35e350aded        5 months ago        203MB

4. Create container validation

[root@docker mysql]# docker run -d -P mysqld:new 
[root@docker mysql]# docker ps -a
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                     NAMES
fff4ac6a524f        mysqld:new          "mysqld_safe"       4 seconds ago       Up 3 seconds        0.0.0.0:32777->3306/tcp   infallible_babbage
#Enter the container to set the permission account of mysql
[root@docker mysql]# docker exec -it fff4ac6a524f /bin/bash
[root@fff4ac6a524f ~]# mysql -uroot -p
mysql> grant all privileges on *.* to 'root'@'localhost' identified by '123456';
mysql> grant all privileges on *.* to 'root'@'%' identified by '123456';
#Test and verify the mysql client installed on the host
[root@docker mysql]# yum install mariadb -y
[root@docker ~]# mysql -h 192.168.7.168 -uroot -p123456 -P 32777
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MySQL connection id is 2
Server version: 5.7.26 Source distribution

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MySQL [(none)]>

Summary:
The above are some common cases of using dockerfile to create images. When using dockerfile to create images, the most important thing is the process of writing dockerfile files. We need to know the significance of each step of operation, and be careful not to make mistakes due to the use of some regular expressions.

Topics: Linux Docker MySQL Nginx Tomcat