Docker ホストを作る
Docker入門1日目のメモ。
インストールしたてのCentOS7にDockerをインストールして、イメージ作って、コンテナ作るまでを書いておく。
構成
- CentOS7
ネットワーク構成
Internet
|
router(nat)
|
--o-----o-----o-- 10.0.2.0/24
| |
dhcp | .15
enp0s3
centos7
enp0s8
| .101
|
--o-----o-----o--- 192.168.99.0/24
| |
dhcp windows
ハードウェア構成
- centos7
- Mem: 1024MB
- CPU: 1
- Disk: 8GB
手順
Dockerをインストールする
CentOS7 を最小構成でインストールする。
コンソールで操作する。
nmcli c up enp0s8
hostname -I
# --> 192.168.99.101
hostnamectl set-hostname centos7
windowsからSSHで操作する。
ssh root@192.168.99.101
nmcli c modify enp0s8 connection.autoconnect yes
nmcli c modify enp0s3 connection.autoconnect yes
yum update -y
yum install yum-utils -y
needs-restarting
systemctl reboot
ping -t 192.168.99.101
ssh root@192.168.99.101
yum install -y yum-utils device-mapper-persistent-data lvm2
yum-config-manager \
--add-repo https://download.docker.com/linux/centos/docker-ce.repo
yum install docker-ce docker-ce-cli containerd.io -y
systemctl enable docker
systemctl start docker
docker run hello-world
ログ
# docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
1b930d010525: Pull complete
Digest: sha256:2557e3c07ed1e38f26e389462d03ed943586f744621577a99efb77324b0fe535
Status: Downloaded newer image for hello-world:latest
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
(amd64)
3. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal.
To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/
For more examples and ideas, visit:
https://docs.docker.com/get-started/
docker コマンドの機能一覧を得る
# docker
Usage: docker [OPTIONS] COMMAND
A self-sufficient runtime for containers
Options:
--config string Location of client config files
(default "/root/.docker")
-D, --debug Enable debug mode
-H, --host list Daemon socket(s) to connect to
-l, --log-level string Set the logging level
("debug"|"info"|"warn"|"error"|"fatal") (default "info")
--tls Use TLS; implied by --tlsverify
--tlscacert string Trust certs signed only by this CA
(default "/root/.docker/ca.pem")
--tlscert string Path to TLS certificate file (default
"/root/.docker/cert.pem")
--tlskey string Path to TLS key file (default
"/root/.docker/key.pem")
--tlsverify Use TLS and verify the remote
-v, --version Print version information and quit
Management Commands:
builder Manage builds
config Manage Docker configs
container Manage containers
engine Manage the docker engine
image Manage images
network Manage networks
node Manage Swarm nodes
plugin Manage plugins
secret Manage Docker secrets
service Manage services
stack Manage Docker stacks
swarm Manage Swarm
system Manage Docker
trust Manage trust on Docker images
volume Manage volumes
Commands:
attach Attach local standard input, output, and error streams to a running container
build Build an image from a Dockerfile
commit Create a new image from a container's changes
cp Copy files/folders between a container and the local filesystem
create Create a new container
diff Inspect changes to files or directories on a container's filesystem
events Get real time events from the server
exec Run a command in a running container
export Export a container's filesystem as a tar archive
history Show the history of an image
images List images
import Import the contents from a tarball to create a filesystem image
info Display system-wide information
inspect Return low-level information on Docker objects
kill Kill one or more running containers
load Load an image from a tar archive or STDIN
login Log in to a Docker registry
logout Log out from a Docker registry
logs Fetch the logs of a container
pause Pause all processes within one or more containers
port List port mappings or a specific mapping for the container
ps List containers
pull Pull an image or a repository from a registry
push Push an image or a repository to a registry
rename Rename a container
restart Restart one or more containers
rm Remove one or more containers
rmi Remove one or more images
run Run a command in a new container
save Save one or more images to a tar archive (streamed to STDOUT by default)
search Search the Docker Hub for images
start Start one or more stopped containers
stats Display a live stream of container(s) resource usage statistics
stop Stop one or more running containers
tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
top Display the running processes of a container
unpause Unpause all processes within one or more containers
update Update configuration of one or more containers
version Show the Docker version information
wait Block until one or more containers stop, then print their exit codes
Run 'docker COMMAND --help' for more information on a command.
イメージからコンテナを作ってシェルを使う
centosがなければ、ダウンロードする。
centosはDocker公式イメージの１つ。
docker run -it centos bash
exit で終了する
centosイメージで SELinux が有効か調べる
docker run -it centos bash
yum provides '*bin/getenforce'
yum install libselinux-utils -y
getenforce
# --> Disabled
イメージの一覧を得る
docker image ls
イメージを作る
標準出力に出力するイメージを作る
mkdir -pv $HOME/dir1
cd $HOME/dir1
cat <<'__DOCKERFILE__' | tee $HOME/dir1/Dockerfile >/dev/null
FROM centos
MAINTAINER kumarstack55 <kumarstack55@gmail.com>
CMD echo a
__DOCKERFILE__
docker build --tag=tag1 .
docker image ls
# 実行してみる
docker run tag1
# --> a
httpd をサービスするイメージを作る
mkdir -pv $HOME/dir2
cd $HOME/dir2
cat <<'__DOCKERFILE__' | tee $HOME/dir2/Dockerfile >/dev/null
FROM centos
MAINTAINER kumarstack55 <kumarstack55@gmail.com>
RUN yum install httpd -y
RUN echo 'ServerName localhost:80' >/etc/httpd/conf.d/servername.conf
RUN echo '<html><body>a</body></html>' >/var/www/html/index.html
EXPOSE 80
CMD /usr/sbin/httpd -D FOREGROUND
__DOCKERFILE__
docker build --tag=tag2 .
docker image ls
実行してみる
docker run -d -p 10080:80 tag2
windows で次のURLを見る。
http://192.168.99.101:10080/
# --> a
centos7 で docker コンテナを止める。
ここでは filter で指定タグを探しているが、
ancestor は範囲に子を含むので、微妙。
もっといい方法がありそう。
docker ps
docker ps --filter ancestor=tag2 --format "{{.ID}}"
docker stop $(docker ps --filter ancestor=tag2 --format "{{.ID}}")
イメージからコンテナを作る
再掲。
docker run centos7
docker run centos7 -it bash
docker run tag1
docker run -d -p 10080:80 tag2
コンテナの一覧を得る
docker ps
docker ps -a
コンテナを消す
tag2のコンテナを消す。
docker ps --all
docker ps --all --filter ancestor=tag2 --format "{{.ID}}"
docker rm $(docker ps --all --filter ancestor=tag2 --format "{{.ID}}")
イメージを消す
tag1のコンテナを消す。
force で紐づくコンテナもまとめて消してくれる。
事前に docker rm すれば force は不要となる。
docker image ls
docker images tag1 --format "{{.ID}}"
docker rmi $(docker images tag1 --format "{{.ID}}")
docker rmi --force $(docker images tag1 --format "{{.ID}}")
参考資料
Get started with Docker
https://docs.docker.com/get-started/