Contenedores Docker
El repositorio de contenedores para descargar esta en https://hub.docker.com
Cada repositorio tiene diferentes contenedores.Cada contenedor se etiqueta(tag) para poder diferenciarlos.
Para descargar Ubuntu 14.04
$ sudo docker pull ubuntu:trusty trusty: Pulling from library/ubuntu 324d088ce065: Pull complete 2ab951b6c615: Pull complete 9b01635313e2: Pull complete 04510b914a6c: Pull complete 83ab617df7b4: Pull complete Digest: sha256:b8855dc848e2622653ab557d1ce2f4c34218a9380cceaa51ced85c5f3c8eb201 Status: Downloaded newer image for ubuntu:trusty
Si no ponemos etiqueta entonces por defecto se descarga el contenedor con etiqueta «latest».
Vamos a ver las imagenes
$ sudo docker images [sudo] password for jon: REPOSITORY TAG IMAGE ID CREATED SIZE ubuntu trusty 8cef1fa16c77 2 weeks ago 223MB hello-world latest e38bc07ac18e 5 weeks ago 1.85kB busybox latest 8ac48589692a 6 weeks ago 1.15MB
Para borrar imagenes
$ sudo docker rmi 8ac48589692a Error response from daemon: conflict: unable to delete 8ac48589692a (must be forced) - image is being used by stopped container a9ad22be49f3 $
No deja borrarlo porque tiene asociado un contenedor.
Para ver los contenedores que tenemos creados
$ sudo docker ps -a 185d8d93b1cd ubuntu "/bin/bash" 2 hours ago Exited (0) 2 hours ago naughty_lichterman a9ad22be49f3 busybox "sh" 21 hours ago Exited (0) 21 hours ago reverent_lichterman 7487aec705bb hello-world "/hello" 21 hours ago Exited (0) 21 hours ago clever_tereshkova
Para borrar contenedores
$ sudo docker rm a9ad22be49f3 a9ad22be49f3 $ sudo docker rmi 8ac48589692a Untagged: busybox:latest Untagged: busybox@sha256:58ac43b2cc92c687a32c8be6278e50a063579655fe3090125dcb2af0ff9e1a64 Deleted: sha256:8ac48589692a53a9b8c2d1ceaa6b402665aa7fe667ba51ccc03002300856d8c7 Deleted: sha256:0314be9edf00a925d59f9b88c9d8ccb34447ab677078874d8c14e7a6816e21e1 $
Vamos a crear nuestro primer contenedor interactivo :
$ sudo docker run -it ubuntu Unable to find image 'ubuntu:latest' locally latest: Pulling from library/ubuntu a48c500ed24e: Pull complete 1e1de00ff7e1: Pull complete 0330ca45a200: Pull complete 471db38bcfbf: Pull complete 0b4aba487617: Pull complete Digest: sha256:c8c275751219dadad8fa56b3ac41ca6cb22219ff117ca98fe82b42f24e1ba64e Status: Downloaded newer image for ubuntu:latest root@185d8d93b1cd:/#
Nos cambia el prompt y lo identifica con el ID del contenedor.
$ sudo docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 185d8d93b1cd ubuntu "/bin/bash" 2 minutes ago Up 2 minutes naughty_lichterman 7487aec705bb hello-world "/hello" 19 hours ago Exited (0) 19 hours ago clever_tereshkova
Probamos a instalar curl.
root@185d8d93b1cd:/# apt-get update
root@185d8d93b1cd:/# apt-get install curl Reading package lists... Done Building dependency tree Reading state information... Done The following additional packages will be installed: ca-certificates krb5-locales libasn1-8-heimdal libcurl4 libgssapi-krb5-2 libgssapi3-heimdal libhcrypto4-heimdal libheimbase1-heimdal libheimntlm0-heimdal libhx509-5-heimdal libk5crypto3 libkeyutils1 libkrb5-26-heimdal libkrb5-3 libkrb5support0 libldap-2.4-2 libldap-common libnghttp2-14 libpsl5 libroken18-heimdal librtmp1 libsasl2-2 libsasl2-modules libsasl2-modules-db libsqlite3-0 libssl1.1 libwind0-heimdal openssl publicsuffix Suggested packages: krb5-doc krb5-user libsasl2-modules-gssapi-mit | libsasl2-modules-gssapi-heimdal libsasl2-modules-ldap libsasl2-modules-otp libsasl2-modules-sql The following NEW packages will be installed: ca-certificates curl krb5-locales libasn1-8-heimdal libcurl4 libgssapi-krb5-2 libgssapi3-heimdal libhcrypto4-heimdal libheimbase1-heimdal libheimntlm0-heimdal libhx509-5-heimdal libk5crypto3 libkeyutils1 libkrb5-26-heimdal libkrb5-3 libkrb5support0 libldap-2.4-2 libldap-common libnghttp2-14 libpsl5 libroken18-heimdal librtmp1 libsasl2-2 libsasl2-modules libsasl2-modules-db libsqlite3-0 libssl1.1 libwind0-heimdal openssl publicsuffix 0 upgraded, 30 newly installed, 0 to remove and 0 not upgraded. Need to get 4580 kB of archives. After this operation, 14.1 MB of additional disk space will be used. Do you want to continue? [Y/n]
Salimos del contenedor.
root@185d8d93b1cd:/# exit exit $
Para parar un contenedor :
$ sudo docker stop 185d8d93b1cd
Para volver a entrar en el contenedor.
$ sudo docker start -i 185d8d93b1cds root@185d8d93b1cd:/#
Para ejecutar contenedores en background.
-d, –detach
$ sudo docker run -d nginx Unable to find image 'nginx:latest' locally latest: Pulling from library/nginx f2aa67a397c4: Pull complete 3c091c23e29d: Pull complete 4a99993b8636: Pull complete Digest: sha256:0fb320e2a1b1620b4905facb3447e3d84ad36da0b2c8aa8fe3a5a81d1187b884 Status: Downloaded newer image for nginx:latest 962392723bf524cfe0d17ecc6b9f5d3ca72683e500b5406d6292e6e466c93f69
$ sudo docker ps CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 962392723bf5 nginx "nginx -g 'daemon of…" 2 minutes ago Up 2 minutes 80/tcp brave_ramanujan
Creamos un contenedor con un nombre especifico.
$ sudo docker run -it --name contenedor_ubuntu ubuntu root@29d208c2f162:/#
$ sudo docker ps 29d208c2f162 ubuntu "bash" 8 minutes ago Up 8 minutes contenedor_ubuntu
Para poder ejecutar comandos en el contenedor.
$ sudo docker exec -it contenedor_ubuntu date Fri May 18 14:40:14 UTC 2018
Para aglutinar todos los comandos relacionados con imagenes tenemos el comando «docker image».
$ sudo docker image --help Usage: docker image COMMAND Manage images Options: Commands: build Build an image from a Dockerfile history Show the history of an image import Import the contents from a tarball to create a filesystem image inspect Display detailed information on one or more images load Load an image from a tar archive or STDIN ls List images prune Remove unused images pull Pull an image or a repository from a registry push Push an image or a repository to a registry rm Remove one or more images save Save one or more images to a tar archive (streamed to STDOUT by default) tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE
Para aglutinar todos los comandos relacionados con contenedores tenemos el comando docker container.
$ sudo docker container --help Usage: docker container COMMAND Manage containers Options: Commands: attach Attach local standard input, output, and error streams to a running container 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 exec Run a command in a running container export Export a container's filesystem as a tar archive inspect Display detailed information on one or more containers kill Kill one or more running containers logs Fetch the logs of a container ls List containers pause Pause all processes within one or more containers port List port mappings or a specific mapping for the container prune Remove all stopped containers rename Rename a container restart Restart one or more containers rm Remove one or more containers run Run a command in a new container 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 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 wait Block until one or more containers stop, then print their exit codes
Para ver lo que esta mostrando un contenedor en background.
$ sudo docker logs contenedor_ubuntu --tail 10
Para matar un contenedor en background.
$ sudo docker kill contenedor_ubuntu
Para ver los recursos que esta consumiendo un contendor.
$ sudo docker top contenedor_ubuntu
o tambien podemos ultilizar
$ sudo docker stats contenedor_ubuntu
Para ver las propiedades y características de contenedores e imágenes en formato JSON.
$ sudo docker inspect contenedor_ubuntu
Ejecutar un bash dentro de un contenedor de ubnutu1.
$ docker exec -it ubuntu1 bash
