Docker introduction
- It's a lightweight "virtual machine"
- Open source tools for running applications in Linux containers
The difference between Docker and virtual machine
- Virtual machine is a physical machine, using virtualization technology, virtual out of multiple operating systems, each operating system is isolated. Docker is an open source application container engine. You still need to install the operating system on the computer first, and then install the docker container manager. Virtual machines are virtualized at the hardware level, while dockers are virtualized at the operating system level; virtual machines are operating systems built by simulating hardware
Using scenario of Docker
- Packaged applications simplify deployment
- Free migration from underlying hardware
- For example: the server moves from Tencent cloud to Alibaba cloud
Docker core concepts
- image
- container
- Warehouse
Two ways to install Docker in CentOS
- Using curl to obtain the installation script of docker for installation
- Use yum warehouse to install docker
Installation of docker
Set image source and install docker
[root@localhost ~]# yum install -y \ > yum-utils \ //Set source tool > device-mapper-persistent-data \ //Mapping tool > lvm2 [root@localhost ~]# Yum config Manager -- add repo https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo / / load alicloud image source [root@localhost ~]# Yum install docker ce - Y / / install the docker container [root@localhost ~]# systemctl stop firewalld.service [root@localhost ~]# setenforce 0 [root@localhost ~]# systemctl start docker / / open the docker container [root@localhost ~]# systemctl enable docker / / set boot to start automatically [root@localhost ~]# ps aux | grep docker / / check whether the docker process is enabled [root@localhost ~]# docker version / / view version [root@localhost ~]# docker search nginx / / search the public image [root@localhost ~]# docker pull nginx / / download the image
Image acceleration
-
Log in to alicloud website - console - Product Service - container image service - image accelerator - choose centos
[root@localhost ~]# TEE / etc / docker / daemon. JSON < - 'EOF' / / image acceleration > { > "registry-mirrors": ["https://3a8s9zx5.mirror.aliyuncs.com"] > } > EOF { "registry-mirrors": ["https://3a8s9zx5.mirror.aliyuncs.com"] } [root@localhost ~]# Systemctl daemon reload / / reload the Daemons [root@localhost ~]# systemctl restart docker / / restart the docker service [root@localhost ~]# docker pull nginx / / download the nginx image [root@localhost ~]# docker images / / view the downloaded image information REPOSITORY TAG IMAGE ID CREATE SIZE nginx latest f7bb5701a33c 4 days ago 126MB
Basic operation of docker image
- Container 1: 192.168.80.12
- Container 2: 192.168.80.13
[root@localhost ~]# docker inspect f7bb5701a33c / / view the image information [root@localhost ~]# docker tag nginx:latest nginx:web / / add a new tag [root@localhost ~]# docker images / / view the image REPOSITORY TAG IMAGE ID CREATED SIZE nginx latest f7bb5701a33c 4 days ago 126MB nginx web f7bb5701a33c 4 days ago 126MB //Regenerate a mirror image, the original image will not disappear [root@localhost ~]# docker images | grep web / / view the image labeled web nginx web f7bb5701a33c 4 days ago 126MB [root@localhost ~]# docker rmi nginx:web / / delete the image, or directly follow the ID number Untagged: nginx:web [root@localhost ~]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE nginx latest f7bb5701a33c 4 days ago 126MB [root@localhost ~]# cd /opt/ [root@localhost opt]# Docker save - O nginx nginx: latest / / save the image [root@localhost opt]# ls containerd nginx rh [root@localhost opt]# scp /opt/nginx [email protected]:/opt / / / remote copy to 13 server
Open another virtual machine with docker (192.168.80.13)
[root@localhost opt]# Docker load < nginx / / load image //Or use docker load --input to save the filename [root@localhost opt]# docker images / / view image information REPOSITORY TAG IMAGE ID CREATED SIZE nginx latest f7bb5701a33c 4 days ago 126MB
Back to the original virtual machine (192.168.80.12)
[root@localhost opt]# docker tag nginx:latest nginx:web / / modify tag [root@localhost opt]# docker login / / log in to docker (you need to register) Username: //User name Password: //Password [root@localhost opt]# docker push nginx:web / / upload public warehouse
Basic operation of docker container
[root@localhost opt]# docker create -it nginx:latest /bin/bash / / create a container based on the image - i keep the container's standard input open, - t let docker assign a pseudo terminal 36fdfb0925ba040c094d585d70a3481bd450c7d39e6636ceeb10b5c1b9743593 [root@localhost opt]# Docker PS - A / / - a lists the most recently started containers CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 36fdfb0925ba nginx:latest "/bin/bash" 3 seconds ago Created mystifying_dijkstra [root@localhost opt]# docker start 36fdfb0925ba / / open the container 36fdfb0925ba [root@localhost opt]# docker ps -a / / check that the container status is on CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 36fdfb0925ba nginx:latest "/bin/bash" 16 minutes ago Up 6 seconds 80/tcp mystifying_dijkstra
Operation steps
[root@localhost opt]# docker search centos7 / / view the centos7 image [root@localhost opt]# docker pull paigeeworld/centos7 / / download the image [root@localhost opt]# docker images / / view the image REPOSITORY TAG IMAGE ID CREATED SIZE nginx latest f7bb5701a33c 4 days ago 126MB nginx web f7bb5701a33c 4 days ago 126MB paigeeworld/centos7 latest 4cbe7aa905e7 5 years ago 382MB [root@localhost opt]# docker create -it paigeeworld/centos7 /bin/bash / / create container c48649c8cee9124cb456be4f93882e6dff16f88ba45051731138142d99293dfe [root@localhost opt]# docker ps -a / / view container CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c48649c8cee9 paigeeworld/centos7 "/bin/bash" 4 seconds ago Created relaxed_curran 36fdfb0925ba nginx:latest "/bin/bash" 24 minutes ago Exited (0) 3 minutes ago mystifying_dijkstra [root@localhost opt]# docker start c48649c8cee9 / / open the container c48649c8cee9 [root@localhost opt]# docker ps -a / / view container CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c48649c8cee9 paigeeworld/centos7 "/bin/bash" 34 seconds ago Up 7 seconds relaxed_curran 36fdfb0925ba nginx:latest "/bin/bash" 24 minutes ago Exited (0) 3 minutes ago
Basic operation of container
[root@localhost opt]# Docker run paigeeworld / centos7 / usr / bin / bash - C LS / / docker run directly downloads the image, creates the container, opens it, enters the container, executes the command, and exits bin boot dev etc home [root@localhost opt]# docker ps -a / / view container CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c48649c8cee9 paigeeworld/centos7 "/bin/bash" 9 minutes ago Up 9 minutes relaxed_curran [root@localhost opt]# docker exec -it c48649c8cee9 /bin/bash / / enter the container (must be open) bash-4.2# ls / bin dev home lib64 media opt root sbin sys usr boot etc lib lost+found mnt proc run srv tmp var bash-4.2# Exit / / exit the container exit [root@localhost opt]# docker ps -a / / at this time, the container is still open CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c48649c8cee9 paigeeworld/centos7 "/bin/bash" 10 minutes ago Up 10 minutes relaxed_curran [root@localhost opt]# docker stop c48649c8cee9 / / close the container c48649c8cee9 [root@localhost opt]# docker ps -a / / at this time, the container is in the exit state CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c48649c8cee9 paigeeworld/centos7 "/bin/bash" 11 minutes ago Exited [root@localhost opt]# docker run -d paigeeworld/centos7 /bin/bash -c "while true;do echo hello;done" / / run continuously in the background, - d run in the background 398f3d27f36b7f59a2167a71e71f61064e4e9a0808dfa13404caec0280a0b9c2 [root@localhost opt]# docker ps -a / / check that the container is always open CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 398f3d27f36b paigeeworld/centos7 "/bin/bash -c 'while..." 9 seconds ago Up 7 seconds [root@localhost opt]# Docker export 36fdfb0925ba > nginx? C / / container export [root@localhost opt]# ls containerd nginx nginx_c rh [root@localhost opt]# scp /opt/nginx_c [email protected]:/opt / / / remote replication to another virtual machine
To another virtual machine
[root@localhost opt]# ls containerd nginx nginx_c rh [root@localhost opt]# Cat nginx | C | docker import - nginx: Web / / container import will generate images without creating containers sha256:1488d058197863aedd46d289eeb11dc39f19a2b855c3ecf383331a4d0bac568c [root@localhost opt]# docker images REPOSITORY TAG IMAGE ID CREATED SIZE nginx web 1488d0581978 5 seconds ago 125MB [root@localhost opt]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES [root@localhost opt]# Docker PS - a | awk '' | bash / / batch delete container
docker resource control
Limit cpu usage rate
- Limit cpu usage with the -- cpu quota option
- Implementation by modifying the configuration file cpu.cfs
Multitasking share cpu in proportion
- Docker run -- CPU shares 1024 container A
- Docker run -- CPU shares 1024 container B
- Docker run -- CPU shares 2048 container C
Use the -- cpuse CPUs option to restrict cpu kernel usage
[root@localhost opt]# Docker run -- CPU quota 20000 nginx: latest / / set 20% limit [root@localhost opt]# cd /sys/fs/cgroup/cpu/docker/ [root@localhost opt]# cat cpu.cfs_quota_us -1 [root@localhost opt]# Docker run - ITD -- name c1 -- cpu shares 512 paigeeworld / centos7 / / create container c1 and set weight, so that the cpu resources of c1 and c2 account for 33.3% and 66.7% ec4ab03a7969eebe4746cfe67184bc2c6f9c97e81b22bc2ffab452820a78a0a7 [root@localhost opt]# docker run -itd --name c2 --cpu-shares 1024 paigeeworld/centos7 c688b014329c6a33b0d66947f4489a1a1cb6febc321090ecb4a82b68ae6df250 [root@localhost opt]# docker ps -a / / view container CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES c688b014329c paigeeworld/centos7 "/bin/bash" About a minute ago Up About a minute c2 ec4ab03a7969 paigeeworld/centos7 "/bin/bash" About a minute ago Up About a minute c1 [root@localhost opt]# Docker run -- name C3 -- cpuset CPUs 0,1 paigeeworld / centos7 / / restrict the container to use the specified cpu [root@localhost opt]# docker ps -a / / view container information CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 751409a81682 paigeeworld/centos7 "/bin/bash" 8 seconds ago Exited (0) 7 seconds ago c3 [root@localhost opt]# docker run --name c5 -m 512m paigeeworld/centos7 / / memory usage limit [root@localhost opt]# docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 8c3101668345 paigeeworld/centos7 "/bin/bash" 5 seconds ago Exited (0) 4 seconds ago c5
Restrictions on blkio
--device-read-bps: Limit the amount of data for a device --device-write-bps: Limit the amount of data written to a device --device-read-iops: Limit the number of times to read a device --device-write-iops: Limit the number of writes to a device [root@localhost opt]# docker run -d --device-write-bps /dev/sda:30mb paigeeworld/centos7
Data management of docker
Data management operations
- Easy to view the data generated in the container
- Data sharing among multiple containers
Two management methods
- Data volume
- Data volume container
Data volume
- Data volume is a special directory for container use
Data volume container
- Data volume container is a common container
Data volume sharing (sharing between host and container)
[root@localhost ~]# docker pull centos / / Download Image [root@localhost ~]# docker run -v /var/www:/data1 --name web1 -it centos /bin/bash / / associate the sharing of host and container [root@2483bee94f1a /]# cd data1/ [root@2483bee94f1a data1]# echo "123" > test01.txt [root@2483bee94f1a data1]# exit exit [root@localhost ~]# cat /var/www/test01.txt 123
Data volume container sharing (container and container)
[root@localhost ~]# docker run --name web100 -v /data1 -v /data2 -it centos /bin/bash / / create a web100 container with two volumes of data1, 2 [root@ba6a328c068e /]# cd data1/ [root@ba6a328c068e data1]# Echo "111" > 111.txt / / write contents to the directory respectively [root@ba6a328c068e data1]# cd ../data2/ [root@ba6a328c068e data2]# echo "222" > 222.txt [root@ba6a328c068e data2]# exit exit [root@localhost ~]# Docker run - it -- volumes from web100 - it CentOS / bin / bash / / mount the new container to web100 [root@3f64be49dadd /]# cat data1/111.txt 111 [root@3f64be49dadd /]# cat data2/222.txt 222