On Linux, cgroups and Docker CPU stats deal in “time slices” of CPU, the number of nanoseconds the CPU has been in use for. To get the percentage, the container cgroup value of “time used” is compared to the overall system value for “time available” from /proc/stat. Due to the stored “time slice” values being … Read more
On Docker Toolbox If you are in docker toolbox try the docker client from terminal and then make the configs: docker-machine ssh sudo sysctl -w vm.max_map_count=262144 exit On Docker For Mac: The vm_max_map_count setting must be set within the xhyve virtual machine: $ screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty If it asks you for a username and passwordLog in … Read more
Yes, Docker images are layered. When you build a new image, Docker does this for each instruction (RUN, COPY etc.) in your Dockerfile: create a temporary container from the previous image layer (or the base FROM image for the first command; run the Dockerfile instruction in the temporary “intermediate” container; save the temporary container as … Read more
It is possible to grant a container access to docker so that it can spawn other containers on your host. You do this by exposing the docker socket inside the container, e.g: docker run -v /var/run/docker.sock:/var/run/docker.sock –name containerB myimage … Now, if you have the docker client available inside the container, you will be able … Read more
Firstly, etc/hosts is a networking file present on all linux systems, it is not related to drives or docker. Secondly, if you want to access part of the host filesystem inside a Docker container you need to use volumes. Using the -v flag in a docker run command you can specify a directory on the … Read more
That Docker Hub history view doesn’t show the actual Dockerfile; instead, it shows content essentially extracted from the docker history of the image. That doesn’t preserve the specific details you’re looking for: it doesn’t remember the names of base images, or the build-context file names of things that get ADDed or COPYed in. Chasing through … Read more
You cannot remove images having multiple repositories without the force modifier, see Docker docs for more info. docker images REPOSITORY TAG IMAGE ID CREATED SIZE repository/image-name tag a8e6fa672e89 10 days ago 344MB repository2/image-name tag a8e6fa672e89 10 days ago 344MB If you want to do it manually, instead of using the image id to remove the … Read more
By default, docker container will exit immediately if you do not have any task running on the container. To keep the container running in the background, try to run it with –detach (or -d) argument. For examples: docker pull debian docker run -t -d –name my_debian debian e7672d54b0c2 docker ps -a CONTAINER ID IMAGE COMMAND … Read more
You can also use –force , -f Force removal of the image If you use the -f flag and specify the image’s short or long ID, then this command untags and removes all images that match the specified ID. docker rmi -f <image_id> Note: this command removes images being used by containers.