![]() We’ll just use a simple “HELLO=WORLD” variable for this example:Ĭlick Finish to complete this wizard, and then click OK to exit out of the Preferences menu:Īt the end of the wizard, if the base container is not available already on your system, you will need to initiate a docker-pull. A lot of Docker containers will use that for their configuration. Next, you can configure environment variables that will be accessible inside the container. (the full list of console types are currently telnet, vnc, http, https, and none) It’s set to “Telnet” by default, which is fine for this example, so just click Next>: On the next screen you’ll choose a Console type from a dropdown menu. It’s like the init process on a standard Linux. Those are just two simple examples of why you’d use more than a single interface for a container ) You could also have a container running an open-source firewall. (it’s entirely possible to create a docker container based off of Debian with FRRouting installed, and have it run OSPF, BGP, or IS-IS, and act as a temporary light router. Since This example will just be using the Alpine container as a host, it’ll be left at the default of 1: ![]() Next, you’ll assign how many adapters this container should have. In this instance, it’ll just be called “alpine”, and that’s what it will be listed as in the End Devices toolbar: ![]() On the next screen, give the container a name. You’d enter the GNS3 VM’s shell (or just use a terminal in Linux), and run “docker pull alpine:latest”, and any changes will be pulled down from Docker Hub, and applied the existing container. The reason to use “latest”, as opposed to using a specific version number, is so you can easily upgrade this container to the latest version on Docker Hub. Select “New Image”, and in the dialog box, type alpine:latest, as shown below, and then click Next >: On the next screen, we’ll elect to use the alpine docker container from Docker Hub. You can see all the alpine linux versions available for Docker here: We will use for this example an image of Alpine Linux 3.2, which is a very lightweight Linux distribution. This will not work on GNS3 because we need to configure the IP address inside the container (in standard usage, docker take care of the networking and you can not access containers directly from the network) Please note that most containers start a daemon and expose ports. gns3a appliance file, use the “import appliance” wizard, and follow the direction). There are many freely available containers over on Docker Hub ( ), as well as in the GNS3 Marketplace (you’d simply use download the relevant. You will need to select the container you wish to use. ![]() (Running GNS3 natively in Linux would allow this container to run via the local server, or if GNS3 had been configured to use a remote server, that option would be available, too) Since this article is being written on a Win 10 Pro desktop that has the GNS3 VM running in WS Pro 15.5, that’s the only available option: Next, select the server you wish to run the container with. Go to Edit->Preferences->Docker containers and click on New: If you want to simulate real life container infrastructure, you need to deploy an OS in a Qemu VM, and start the containers in it. It’s also not designed to control a docker cluster for production or development. All of the layers beneath it are read-only. Only the top-most layer in a docker container is actually read/write. The idea isn’t to simulate the deployment of container infrastructure in production, but to use containers as light virtual machines, replacing heavy qemu VMs instances or VPCS, for times when you want to use tools like telnet, nmap, etc… Docker containers are available from a registry, so you can fork them in order to add your own tools. This means containers consume far less RAM and CPU resources overall, per instance, and have a smaller storage footprint. Advantages of Containers versus QEMU VMS Ĭontainers use services provided by the kernel in the host OS (meaning the GNS3 VM or the local machine, if running GNS3 natively in Linux), and not relying on the kernel provided by the OS installed within a Qemu VM. Work on this feature was started by Goran Cetusic during the Google Summer Of Code and finished by the GNS3 core team.īernhard Ehlers and AJ Nouri contributed a lot of their time to the testing/validation of this feature, and Andras Dosztal has added many containers as appliances available in the Marketplace (like the Network Automation container, for example). Docker container support was added as a feature starting with GNS3 1.5.
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