podman/docs/tutorials/podman_tutorial.md

Basic Setup and Use of Podman

Podman is a utility provided as part of the libpod library. It can be used to create and maintain containers. The following tutorial will teach you how to set up Podman and perform some basic commands with Podman.

Install Podman on Fedora

Many of the basic components to run Podman are readily available from the Fedora RPM repositories; the only exception is Podman itself. In this section, we will help you install all the runtime and build dependencies for Podman until an RPM becomes available.

Installing build and runtime dependencies

# sudo dnf install -y git runc libassuan-devel golang golang-github-cpuguy83-go-md2man glibc-static \
                                    gpgme-devel glib2-devel device-mapper-devel libseccomp-devel \
                                    atomic-registries iptables skopeo-containers containernetworking-cni \
                                    conmon

Building and installing podman

# git clone https://github.com/projectatomic/libpod/ ~/src/github.com/projectatomic/libpod
# cd !$
# make
# sudo make install PREFIX=/usr

You now have a working podman environment. Jump to [Familiarizing yourself with Podman](Familiarizing yourself with Podman) to begin using Podman.

Install podman on Ubuntu

The default Ubuntu cloud image size will not allow for the following exercise to be done without increasing its capacity. Be sure to add at least 5GB to the image. Instructions to do this are outside the scope of this tutorial. For this tutorial, the Ubuntu artful-server-cloudimg image was used.

Installing build and runtime dependencies

Installing base packages

# sudo apt-get update
# sudo apt-get install libdevmapper-dev libglib2.0-dev libgpgme11-dev golang libseccomp-dev \
                        go-md2man libprotobuf-dev libprotobuf-c0-dev libseccomp-dev

Building and installing conmon

# git clone https://github.com/kubernetes-incubator/cri-o ~/src/github.com/kubernetes-incubator/cri-o
# cd ~/src/github.com/kubernetes-incubator/cri-o
# mkdir bin
# make conmon
# sudo install -D -m 755 bin/conmon /usr/libexec/crio/conmon

Adding required configuration files

# sudo mkdir -p /etc/containers
# sudo curl https://raw.githubusercontent.com/projectatomic/registries/master/registries.fedora -o /etc/containers/registries.conf
# sudo curl https://raw.githubusercontent.com/projectatomic/skopeo/master/default-policy.json -o /etc/containers/policy.json

Installing CNI plugins

# git clone https://github.com/containernetworking/plugins.git ~/src/github.com/containernetworking/plugins
# cd ~/src/github.com/containernetworking/plugins
# ./build.sh
# sudo mkdir -p /usr/libexec/cni
# sudo cp bin/* /usr/libexec/cni

Installing runc

# git clone https://github.com/opencontainers/runc.git ~/src/github.com/opencontainers/runc
# cd ~/src/github.com/opencontainers/runc
# GOPATH=~/ make static BUILDTAGS="seccomp selinux"
# sudo cp runc /usr/bin/runc

Building and installing Podman

# git clone https://github.com/projectatomic/libpod/ ~/src/github.com/projectatomic/libpod
# cd ~/src/github.com/projectatomic/libpod
# make
# sudo make install PREFIX=/usr

Familiarizing yourself with Podman

Running a sample container

This sample container will run a very basic httpd server that serves only its index page.

# sudo podman run -dt -e HTTPD_VAR_RUN=/var/run/httpd -e HTTPD_MAIN_CONF_D_PATH=/etc/httpd/conf.d \
                    -e HTTPD_MAIN_CONF_PATH=/etc/httpd/conf \
                    -e HTTPD_CONTAINER_SCRIPTS_PATH=/usr/share/container-scripts/httpd/ \
                    registry.fedoraproject.org/f26/httpd /usr/bin/run-httpd

Because the container is being run in detached mode, represented by the -d in the podman run command, podman will print the container ID after it has run.

Listing running containers

The Podman ps command is used to list creating and running containers.

# sudo podman ps

Note: If you add -a to the ps command, Podman will show all containers.

Executing a command in a running container

You can use the exec subcommand to execute a command in a running container. Eventually you will be able to obtain the IP address of the container through inspection, but that is not enabled yet. Therefore, we will install iproute in the container. Notice here that we use the switch --latest as a shortcut for the latest created container. You could also use the container's ID listed during podman ps in the previous step or when you ran the container.

# sudo podman exec --latest -t dnf -y install iproute
# sudo podman exec --latest -t ip a

Note the IP address of the ethernet device.

Testing the httpd server

Now that we have the IP address of the container, we can test the network communication between the host operating system and the container using curl. The following command should display the index page of our containerized httpd server.

# curl http://<IP_address>:8080

Viewing the container's logs

You can view the container's logs with Podman as well:

# sudo podman logs --latest

Stopping the container

To stop the httpd container:

# sudo podman stop --latest

You can also check the status of one or more containers using the ps subcommand. In this case, we should use the -a argument to list all containers.

# sudo podman ps -a

Removing the container

To remove the httpd container:

# sudo podman rm --latest

You can verify the deletion of the container by running podman ps -a.

More information

For more information on Podman and its subcommands, checkout the asciiart demos on the README page.