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[Docker] How-To

Olivier | How-To | 54

Install on CentOs (7)

sudo tee /etc/yum.repos.d/docker.repo <<-'EOF'
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF

yum install docker-engine
systemctl enable docker.service
systemctl start docker

docker run --rm hello-world

Install Docker Compose

curl -L https://github.com/docker/compose/releases/download/1.8.0/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
chmod +x /usr/local/bin/docker-compose
docker-compose --version

To init/start a docker compose :

docker-compose build 
docker-compose up -d
New : 

wget -qO- https://get.docker.com/ | sh
usermod -aG docker $(whoami)
systemctl enable docker.service
systemctl start docker.service
yum install epel-release
yum install -y python-pip
pip install docker-compose
yum upgrade python*

,

54 thoughts on “[Docker] How-To”

  • Olivier says:
    13/12/2016 at 17:49

    On CentOS 6 : https://www.liquidweb.com/kb/how-to-install-docker-on-centos-6/

    Reply
  • Olivier says:
    27/03/2017 at 12:56

    Enter running container : 

    docker exec -it <CONTAINER_NAME/ID> bash
    Reply
  • Olivier says:
    28/03/2017 at 07:31

    Issue with IPv4/IPv6 port forwarding :
    https://www.gesellix.net/post/docker-and-ipv6-on-ubuntu-13-10-saucy-salamander/

    In /etc/sysctl.conf :

    net.ipv6.conf.all.forwarding=1

    then reboot the machine or : 

    sysctl -p /etc/sysctl.conf
    Reply
  • Olivier says:
    04/04/2017 at 13:47

    With error like :
    Get https://registry-1.docker.io/v2/: dial tcp: lookup registry-1.docker.io on …

    check :
    https://docs.docker.com/engine/admin/systemd/#http-proxy

    Reply
  • Olivier says:
    25/04/2017 at 13:24

    stop & delete all containers & images : 

    docker stop $(docker ps -a -q)
docker rm -f $(docker ps -a -q)
docker rmi $(docker images -q)
    Reply
  • Olivier says:
    22/05/2017 at 12:58

    to remove unused containers:

    docker rm $(docker ps -qa --no-trunc --filter "status=exited")

    to remove unused images :

    docker rmi $(docker images --filter "dangling=true" -q --no-trunc)

    https://stackoverflow.com/questions/32723111/how-to-remove-old-and-unused-docker-images

    To remove untagged images : 

    docker images --no-trunc | grep '<none>' | awk '{ print $3 }' | xargs -r docker rmi
    Reply
    • Olivier says:
      27/03/2018 at 09:38

      Remove :
      – all unused images
      – all stopped containers
      – all volumes not used by at least one container
      – all networks not used by at least one container

      docker system prune --volumes --all --force
      docker system prune --volumes --force
      Reply
  • Olivier says:
    14/09/2017 at 06:11

    Commit a container to an image

    docker commit <CONTAINER ID> <IMAGE_NAME>

    Export the image to a file

    docker save <IMAGE_NAME> > /path/to/img_file.tar

    Import the image : 

    docker load < /path/to/img_file.tar
    Reply
  • Olivier says:
    22/09/2017 at 09:35

    Allow unsecure registry (CentOS7)

    echo '{ "insecure-registries":["SERVER_IP:SERVER_PORT"] }' > /etc/docker/daemon.json
service docker restart
    Reply
  • Olivier says:
    22/09/2017 at 13:57

    Default docker home :

    /var/lib/docker
    Reply
  • Olivier says:
    22/09/2017 at 13:58

    Centos : Change docker daemon settings :
    edit:

    /usr/lib/systemd/system/docker.service

    To change home : 

    ExecStart=/usr/bin/dockerd --graph {{docker_home}}

    To change storage driver : 

    ExecStart=/usr/bin/dockerd --storage-driver=devicemapper

    To increase default image size : 

    ExecStart=/usr/bin/dockerd --storage-opt dm.basesize=20G
    Reply
  • Olivier says:
    28/09/2017 at 09:23

    Add another user to docker group : 

    groupadd docker
usermod -aG docker $USER
    Reply
    • Olivier says:
      30/07/2018 at 10:54

      The mechanism by which adding a user to group docker grants permission to run docker is to get access to the socket of docker at /var/run/docker.sock. If the filesystem that contains /var/run has been mounted with ACLs enabled, this can also be achieved via ACLs.

      setfacl -m user:username:rw /var/run/docker.sock
      Reply
  • Olivier says:
    28/09/2017 at 09:25

    Network :

    Create / Delete a network

    docker network ls
docker network create MY_NETWORK_NAME
docker network rm MY_NETWORK_NAME

    Create a container for this network :

     docker run --network=MY_NETWORK_NAME ...
    Reply
  • Olivier says:
    12/12/2017 at 13:37

    Create a tunnel to the Docker network (allow resolution of containers’s hostnames from host)

    #!/usr/bin/env bash

# Create SSH-SERVER container
docker run -d --name ssh-server -p 32222:22 corbinu/ssh-server

# Add SSH key
cat ~/.ssh/id_rsa.pub | docker exec -i ssh-server /bin/bash -c "cat >> /root/.ssh/authorized_keys"

# Start sshuttle
sshuttle --dns --daemon -vNHr root@127.0.0.1:32222

    if the containers are in a dedicated network, don’t forget to move the ssh-server in the same one (with –network=NETWORK_NAME)

    Reply
  • Olivier says:
    25/01/2018 at 09:02

    Inspect an image : 

    docker inspect IMAGE_NAME/IMAGE_TAG
    Reply
  • Olivier says:
    25/01/2018 at 09:03

    Tag and push : 

    docker tag [OPTIONS] IMAGE[:TAG] [REGISTRYHOST/][USERNAME/]NAME[:TAG]
docker push NAME[:TAG]

    example =

    docker tag 518a41981a6a myRegistry.com/myImage
docker push myRegistry.com/myImage
    Reply
  • Olivier says:
    25/01/2018 at 09:04

    Dockerfile : Add SSH Server (centos/RHEL)

    FROM centos:centos7

RUN yum -y update && yum install -y initscripts openssh openssh-server openssh-clients passwd sed
RUN sshd-keygen
RUN sed -i “s/#UsePrivilegeSeparation.*/UsePrivilegeSeparation no/g” /etc/ssh/sshd_config && sed -i “s/UsePAM.*/UsePAM no/g” /etc/ssh/sshd_config

# setup default user
# RUN useradd admin -G wheel -s /bin/bash -m
# RUN echo ‘admin:welcome’ | chpasswd
# RUN echo ‘%wheel ALL=(ALL) ALL’ >> /etc/sudoers

# expose ports for ssh
EXPOSE 22
CMD    [“/usr/sbin/sshd”, “-D”]
    Reply
  • Olivier says:
    17/05/2018 at 10:55

    CentOS : Upgrade docker version :

    Remove previous versions

    yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-selinux \
                  docker-engine-selinux \
                  docker-engine

    Install dependencies

    yum install -y yum-utils \
  device-mapper-persistent-data \
  lvm2

    Add new repo

    yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo

    Install Docker CE

    yum install -y docker-ce
    Reply
  • Olivier says:
    18/05/2018 at 10:09

    CentOS / Docker / LVM :

    https://docs.docker.com/storage/storagedriver/device-mapper-driver/#configure-direct-lvm-mode-for-production

    Steps =
    – add a new disk
    – create a partition + table partition (gparted)

    pvcreate /dev/sdc1

vgcreate docker /dev/sdc1

lvcreate --wipesignatures y -n thinpool docker -l 95%VG
lvcreate --wipesignatures y -n thinpoolmeta docker -l 1%VG

lvconvert -y --zero n -c 512K --thinpool docker/thinpool --poolmetadata docker/thinpoolmeta

lvchange --metadataprofile docker-thinpool docker/thinpool

lvs -o+seg_monitor

    edit /etc/docker/daemon.json :

    {
"storage-driver": "devicemapper",
"storage-opts": [
    "dm.thinpooldev=/dev/mapper/docker2-thinpool",
    "dm.use_deferred_removal=true",
    "dm.use_deferred_deletion=true",
    "dm.basesize=20G"
],
"insecure-registries":["....lan:5000", "....lan:5000", "....lan"],
"debug": true
}

    delete all docker content (/var/lib/docker)
    restart service

    Reply
  • Olivier says:
    10/10/2018 at 07:34

    Docker behind a proxy (Centos7 & systemctl)

    systemctl enable docker.service
vi /etc/systemd/system/multi-user.target.wants/docker.service

    [Service]
Environment="HTTP_PROXY=http://1.2.3.4:8080" "HTTPS_PROXY=http://1.2.3.4:8080" "NO_PROXY=*.local1.lan,*.local2.lan"
    Reply
  • Olivier says:
    15/10/2018 at 14:24

    Dockerfile, execute command using ENV value : 

    FROM ...

ENV FOO "BAR"

ADD start.sh /start.sh
RUN chmod +x /start.sh
ENTRYPOINT ["/start.sh"]

CMD ["echo", "${FOO}"]

    with start.sh :

    #!/bin/bash

/bin/bash -l -c "$*"
    Reply
  • Olivier says:
    10/04/2019 at 09:40

    Inspect tag from containers/images : 

    docker inspect --format '{{ index .Config.Labels "LABEL_NAME"}}'  CONTAINER_ID
    Reply
  • Olivier says:
    17/07/2019 at 17:05

    Truncate docker JSON log file : 

    truncate -s 0 /var/lib/docker/containers/*/*-json.log

    see also : https://stackoverflow.com/questions/980283/truncating-a-file-while-its-being-used-linux

    Reply
  • Olivier says:
    17/07/2019 at 17:06

    Config Docker daemon for log rotation :

    {
    "log-driver": "json-file",
    "log-opts": {"max-size": "10m", "max-file": "3"}
    }

    Reply
  • Olivier says:
    06/09/2019 at 11:24

    How to determine what containers use the docker volume?

    docker ps -a --filter volume=VOLUME_NAME_OR_MOUNT_POINT
    Reply
  • Olivier says:
    03/10/2019 at 14:31

    When docker cp does not work (docker before 1.8) with Error Path not specified

    cat /local/file/path | docker exec -i <running-container-id> sh -c 'cat > /inside/docker/file/path'
    Reply
  • Olivier says:
    20/11/2019 at 07:41

    Update restart policy for a running container = 

    docker update --restart=on-failure:3 hopeful_morse
    Reply
  • Olivier says:
    20/11/2019 at 07:46

    Enable the live restore setting to keep containers alive when the daemon becomes unavailable 

    "live-restore": true
    Reply
  • Olivier says:
    20/11/2019 at 07:47

    Reload Docker daemon config (without restart) 

    systemctl reload docker
    Reply
  • Olivier says:
    04/03/2020 at 09:56

    Switch from VirutalBox to Docker :

    As outlined here, Docker for Windows requires Hyper-V. This needs to be disabled before you can run VirtualBox.

    # Run from elevated prompt (admin privileges)
bcdedit /set hypervisorlaunchtype off

    And to start using Docker for Windows again, re-enable Hyper-V:

    # Run from elevated prompt (admin privileges)
bcdedit /set hypervisorlaunchtype auto

    see : https://fredrikaverpil.github.io/2018/03/15/switching-between-docker-and-virtualbox-on-windows-10/

    Reply
  • Olivier says:
    30/04/2020 at 09:39

    Install on CentOS7 / RHEL 7 : 

    
yum install -y yum-utils device-mapper-persistent-data lvm2

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

# For RHEL 7 Only
subscription-manager repos --enable=rhel-7-server-extras-rpms

yum install docker-ce
    Reply
  • Olivier says:
    30/04/2020 at 09:46

    Install docker-compose on CentOS7 / RHEL 7 : 

    yum install -y python-pip gcc python-devel
yum upgrade -y python*
pip install pip --upgrade
pip install docker-compose
    Reply
  • OLIVIER COMBE says:
    07/09/2020 at 10:41

    Error : 

    su: /bin/bash: Resource temporarily unavailable

    Check the number of running process on the host machine for the docker container user (not the docker daemon)

    Check also the “defunct” processes : 

    ps -ef | grep defunct
    Reply
  • OLIVIER COMBE says:
    23/09/2020 at 16:38

    Install docker : 

    yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo && yum install -y yum-utils device-mapper-persistent-data lvm2 docker-ce-18* docker-ce-cli-18* && systemctl enable docker.service

    In case of error with container-selinux : 

    Error: Package: 3:docker-ce-18.09.9-3.el7.x86_64 (docker-ce-stable)
           Requires: container-selinux >= 2:2.74
Error: Package: containerd.io-1.3.7-3.1.el7.x86_64 (docker-ce-stable)
           Requires: container-selinux >= 2:2.74

    Execute : 

    subscription-manager repos --enable=rhel-7-server-extras-rpms
    Reply
  • OLIVIER COMBE says:
    05/11/2020 at 12:15

    As it is not possible to expose a new port on a running container, it’s possible to create a 2nd container to expose a port and forward the traffic to the 1st container :

    docker run --rm --network=MY_NETWORK -p PUBLIC_PORT:1234 verb/socat TCP-LISTEN:1234,fork TCP-CONNECT:CONTAINER_IP:CONTAINER_PORT

    For example, to expose port 7001 from container 172.16.0.2 via port 9170 : 

    docker run --rm --network=docker_tsoap_builder -p 9170:1234 verb/socat TCP-LISTEN:1234,fork TCP-CONNECT:172.16.0.2:7001
    Reply
  • OLIVIER COMBE says:
    12/11/2020 at 15:15

    An easy way to keep a container running in detached mode is is to tail the /dev/null device as the CMD or ENTRYPOINT command of your Docker image.

    FROM ...

CMD tail -f /dev/null
    Reply
  • OLIVIER COMBE says:
    24/11/2020 at 11:36

    Crontab and docker
    Error :
    the input device is not a TTY

    Solution : 

    docker exec -i containername /path/to/command

    do not use “-it”

    Reply
  • OLIVIER COMBE says:
    01/12/2020 at 11:39

    Update docker daemon to use a mirror registry (instead of docker.io / docker hub)

    {
"registry-mirrors": ["https://MIRROR_ADDRESS"]
}

    and reload docker daemon 

    systemctl reload docker
    Reply
  • OLIVIER COMBE says:
    10/12/2020 at 10:18

    Remove all images matching a specific string : 

    docker rmi $(docker images --format "{{.Repository}}:{{.Tag}}"|grep "MY_VERSION")
    Reply
  • OLIVIER COMBE says:
    25/01/2021 at 14:02

    List all containers from a specific network : 

    docker network inspect \
  -f '{{ range $key, $value := .Containers }}{{ printf "%s\n" $key}}{{ end }}' \
  <network-id>
    Reply
  • OLIVIER COMBE says:
    12/08/2021 at 13:29

    Attach a volume to a container while it is running :

    https://jpetazzo.github.io/2015/01/13/docker-mount-dynamic-volumes/

    Reply
  • OLIVIER COMBE says:
    15/09/2021 at 13:58

    RHEL 7 :

    Error while installing docker-ce: 

    Requires: container-selinux >= 2:2.74

    Enable RPMS repo : 

    subscription-manager repos --enable=rhel-7-server-extras-rpms
    Reply
  • OLIVIER COMBE says:
    20/04/2022 at 14:01

    Expose docker daemon:

    Update daemon.json file in /etc/docker:

     {"hosts": ["tcp://0.0.0.0:2375", "unix:///var/run/docker.sock"]}

    Add /etc/systemd/system/docker.service.d/override.conf : 

     [Service]
 ExecStart=
 ExecStart=/usr/bin/dockerd

    Reload the systemd daemon:

     systemctl daemon-reload

    Restart docker:

    systemctl restart docker.service

    In case of errors like:
    driver failed programming external connectivity on endpoint XXX”

    # Enter below command, it will clear all chains.
$ sudo iptables -t filter -F
$ iptables -t filter -X
# Then restart Docker Service using below comamnd
$ systemctl restart docker
    Reply
  • OLIVIER COMBE says:
    22/11/2022 at 19:32

    Rester docker config when using directlvm

    # Stop & disable docker
systemctl stop docker
systemctl disable docker

# remove content
rm -Rf /var/lib/docker/*

# check vgname
lsblk
vgdisplay

# remove VG and LV
vgremove <VG_NAME>

# restart docker engine
systemctl enable docker
systemctl start docker
    Reply
  • OLIVIER COMBE says:
    09/01/2023 at 10:13

    Remove all dangling images: 

    docker rmi -f $(docker images --filter "dangling=true")
    Reply
  • OLIVIER COMBE says:
    11/01/2023 at 10:13

    Docker image for Web hello-world:

    https://hub.docker.com/r/tutum/hello-world

    docker pull tutum/hello-world
    Reply
  • OLIVIER COMBE says:
    06/03/2023 at 09:42

    docker / docker-compose Error 

    Error response from daemon: driver failed programming external connectivity on endpoint ssa-data-lab-denodo-platform-1 (9931d77aef1ed553503b017688806196209ce832039288e4b2b7e9092681d45f):  (iptables failed: iptables --wait -t nat -A DOCKER -p tcp -d 0/0 --dport 9999 -j DNAT --to-destination 172.19.0.2:9999 ! -i br-2e8af153dbd8: iptables: No chain/target/match by that name

    Solution:
    Clean iptables chain and restart docker:

    iptables -t filter -F
iptables -t filter -X
systemctl restart docker

    See https://stackoverflow.com/questions/31667160/running-docker-container-iptables-no-chain-target-match-by-that-name

    Reply
  • OLIVIER COMBE says:
    27/04/2023 at 14:41

    docker-compose on RHEL8:

    curl -L "https://github.com/docker/compose/releases/download/1.23.2/docker-compose-$(uname -s)-$(uname -m)" -o docker-compose

sudo mv docker-compose /usr/local/bin 
sudo chmod +x /usr/local/bin/docker-compose

sudo ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose
    Reply
  • OLIVIER COMBE says:
    08/08/2023 at 15:42

    Use network “host”:

    docker cli:

    docker run --network=host ...

    docker-compose:

    version: "3"
services:
  web:
    build: .
    container_name: html-container
    network_mode: "host"
    Reply
  • OLIVIER COMBE says:
    06/03/2024 at 11:17

    Configure concurrent upload/download:
    in /etc/docker/daemon.json

    {
    "max-concurrent-uploads": 1,
    "max-concurrent-downloads": 1
}
    Reply

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