help - Display information about a command The help command displays information about how to use a command. For example, to see a list of Swarm options and commands, enter: $ docker run swarm --help To see a list of arguments and options for a specific Swarm command, enter: $ docker run swarm <command> --help For example: $ docker run swarm list --help Usage: swarm list [OPTIONS] <discovery> List nodes in a cluster Arguments: <discovery> discovery service to use [$S

create — Create a discovery token The create command uses Docker Hub’s hosted discovery backend to create a unique discovery token for your cluster. For example: $ docker run --rm swarm create 86222732d62b6868d441d430aee4f055 Later, when you use manage or join to create Swarm managers and nodes, you use the discovery token in the <discovery> argument (e.g., token://86222732d62b6868d441d430aee4f055). The discovery backend registers each new Swarm manager and node that uses the token as a

Swarm and container networks Docker Swarm is fully compatible with Docker’s networking features. This includes the multi-host networking feature which allows creation of custom container networks that span multiple Docker hosts. Before using Swarm with a custom network, read through the conceptual information in Docker container networking. You should also have walked through the Get started with multi-host networking example. Create a custom network in a Swarm cluster Multi-host networks requi

Swarm — A Docker-native clustering system The swarm command runs a Swarm container on a Docker Engine host and performs the task specified by the required subcommand, COMMAND. Use swarm with the following syntax: $ docker run swarm [OPTIONS] COMMAND [arg...] For example, you use swarm with the manage subcommand to create a Swarm manager in a high-availability cluster with other managers: $ docker run -d -p 4000:4000 swarm manage -H :4000 --replication --advertise 172.30.0.161:4000 consul://172

Docker Swarm strategies The Docker Swarm scheduler features multiple strategies for ranking nodes. The strategy you choose determines how Swarm computes ranking. When you run a new container, Swarm chooses to place it on the node with the highest computed ranking for your chosen strategy. To choose a ranking strategy, pass the --strategy flag and a strategy value to the swarm manage command. Swarm currently supports these values: spread binpack random The spread and binpack strategies compute

Store images on Docker Hub So far you’ve learned how to use the command line to run Docker on your local host. You’ve learned how to pull down images to build containers from existing images and you’ve learned how to create your own images. Next, you’re going to learn how to use the Docker Hub to simplify and enhance your Docker workflows. The Docker Hub is a public registry maintained by Docker, Inc. It contains images you can download and use to build containers. It also provides authenticati

Splunk logging driver The splunk logging driver sends container logs to HTTP Event Collector in Splunk Enterprise and Splunk Cloud. Usage You can configure the default logging driver by passing the --log-driver option to the Docker daemon: docker daemon --log-driver=splunk You can set the logging driver for a specific container by using the --log-driver option to docker run: docker run --log-driver=splunk ... Splunk options You can use the --log-opt NAME=VALUE flag to specify these additional

Select a storage driver This page describes Docker’s storage driver feature. It lists the storage driver’s that Docker supports and the basic commands associated with managing them. Finally, this page provides guidance on choosing a storage driver. The material on this page is intended for readers who already have an understanding of the storage driver technology. A pluggable storage driver architecture Docker has a pluggable storage driver architecture. This gives you the flexibility to “plug

Seccomp security profiles for Docker Secure computing mode (Seccomp) is a Linux kernel feature. You can use it to restrict the actions available within the container. The seccomp() system call operates on the seccomp state of the calling process. You can use this feature to restrict your application’s access. This feature is available only if Docker has been built with seccomp and the kernel is configured with CONFIG_SECCOMP enabled. To check if your kernel supports seccomp: $ cat /boot/config-

Runtime metrics Docker stats You can use the docker stats command to live stream a container’s runtime metrics. The command supports CPU, memory usage, memory limit, and network IO metrics. The following is a sample output from the docker stats command $ docker stats redis1 redis2 CONTAINER CPU % MEM USAGE / LIMIT MEM % NET I/O BLOCK I/O redis1 0.07% 796 KB / 64 MB 1.21% 788 B / 648 B 3.5