Install Docker Snap

2/1/2022by admin
  1. Install Docker Snaps
  2. Install Docker Snap

The difference between Snap, Docker, and Multipass can be easily understood by one example of usage:

Let’s suppose you need to have one LAMP to run codes and possibly share content on the Internet. There come four ways to make it:

Install

Install Docker and Compose into Ubuntu 18.04 Just one command: snap install docker email protected:# snap install docker docker 18.09.9 from Canonical installed It will also install docker-compose. If your Ubuntu 18.04 notifies you do not have snap, you can install it with following command: apt install snap. Snap can now be installed as follows: sudo yum install snapd. Once installed, the systemd unit that manages the main snap communication socket needs to be enabled: sudo systemctl enable -now snapd.socket. To enable classic snap support, enter the following to create a symbolic link between /var/lib/snapd/snap and /snap: sudo ln -s /var/lib. You can simply check the Docker help application packaged in the snap. $ docker.help Docker snap: Docker Linux container runtime. Due to the confinement issues on snappy, it requires some manual setup to make docker-snap works on your machine. We'll take you through the steps needed to set up docker snap work for you on ubuntu core and ubuntu. Sep 08, 2020 Now let’s install Docker on Ubuntu 20.04. Run the following command in the terminal window: sudo apt install docker.io. Type y and hit Enter to confirm the installation. Once the install is completed, the output notifies you Docker has been installed. Step 4: Checking Docker Installation. To verify the installation check the Docker version. I'm running 16.04 (distro= Ubuntu 16.04.1 LTS and kernel= 4.4.0-45-generic) and installed docker by the docker snap. Snap install docker. And here is my snap list. # snap list Name Version Rev Developer Notes docker 1.11.2-9 56 canonical - snapstore-example 0.3 4 noise - ubuntu-core 16.04.1 423 canonical.

1st – The conventional way (reference) would be installing MANUALY the Apache, PHP, MySQL in the Host O.S. The services will use all the libraries, kernel, and any other resource from the Host O.S. The softwares will merge to your system, sharing files, permission, etc. If one of the services crashes the whole Host O.S. can become inoperative, or if one of the services has a vulnerability, all the data becomes vulnerable.

2nd – The Snap way would download and install a self-contained software called ‘snaps’ on the O.S. With absolutely no effort, Snap downloads and install one capsule (app isolation) that contains all the services needed (Apache + PHP + MySQL), all dependencies and libraries (that is why it can run in multiple platforms). The Snap will start and stop all the services at once, as one ‘block’ application that will also run on the O.S. Has the same crash risk as The conventional way (1st).

3rd – The Docker Way would pull (download) one image. This image uses (shares) the host O.S. Kernel, but it creates one whole independent environment, such as users, permissions, file system, etc. This environment is called Container and does not require to boot, so starting/stopping processes are very fast, feel like a light-weight VM, but it is not. There is one shell to get into the container and if one service crashes inside is will most likely not affect the host OS, the same for vulnerabilities, will be kept inside.

4th – The Multipass Way would launch (download and run) one Ubuntu pre-installed image. This will create a bare new Virtual Machine that does not share anything with the host O.S. and does not share any vulnerability or risk in case of a crash. Multipass is not a Hypervisor, it is a tool to quickly and easily start a fresh VM in just one click using the Native hypervisor, in case you need frequently disposable VMs for tests. Inside the VM you have to do The conventional way (1st) to install all softwares and services.

Opinions and applications that I believe would fit better to each:

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Use a Snap package to install the .NET SDK or .NET Runtime. Snaps are a great alternative to the package manager built into your Linux distribution. This article describes how to install .NET through Snap.

A snap is a bundle of an app and its dependencies that works without modification across many different Linux distributions. Snaps are discoverable and installable from the Snap Store. For more information about Snap, see Getting started with Snap.

Caution

Snap packages aren't supported in WSL2 on Windows 10. As an alternative, use the dotnet-install script or the package manager for the particular WSL2 distribution. It's not recommended but you can try to enable snap with an unsupported workaround from the snapcraft forums.

.NET releases

Only ✔️ supported versions of .NET SDK are available through Snap. All versions of the .NET Runtime are available through snap starting with version 2.1. The following table lists the .NET (and .NET Core) releases:

✔️ Supported❌ Unsupported
5.03.0
3.1 (LTS)2.2
2.1 (LTS)2.0
1.1
1.0

For more information about the life cycle of .NET releases, see .NET Core and .NET 5 Support Policy.

SDK or Runtime

Install the SDK (which includes the runtime) if you want to develop .NET apps. Or, if you only need to run apps, install the Runtime. If you're installing the Runtime, we suggest you install the ASP.NET Core Runtime as it includes both .NET and ASP.NET Core runtimes.

If you've already installed the SDK or Runtime, use the dotnet --list-sdks and dotnet --list-runtimes commands to see which versions are installed. For more information, see How to check that .NET is already installed.

Install the SDK

Snap packages for the .NET SDK are all published under the same identifier: dotnet-sdk. A specific version of the SDK can be installed by specifying the channel. The SDK includes the corresponding runtime. The following table lists the channels:

.NET versionSnap package or channel
5.05.0 or latest/stable
3.1 (LTS)3.1 or lts/stable
2.1 (LTS)2.1

Use the snap install command to install a .NET SDK snap package. Use the --channel parameter to indicate which version to install. If this parameter is omitted, latest/stable is used. In this example, 5.0 is specified:

Next, register the dotnet command for the system with the snap alias command:

This command is formatted as: sudo snap alias {package}.{command} {alias}. You can choose any {alias} name you would like. For example, you could name the command after the specific version installed by snap: sudo snap alias dotnet-sdk.dotnet dotnet50. When you use the command dotnet50, you'll invoke this specific version of .NET. But choosing a different alias is incompatible with most tutorials and examples as they expect a dotnet command to be used.

Install the runtime

Snap packages for the .NET Runtime are each published under their own package identifier. The following table lists the package identifiers:

.NET versionSnap package
5.0dotnet-runtime-50
3.1 (LTS)dotnet-runtime-31
3.0dotnet-runtime-30
2.2dotnet-runtime-22
2.1 (LTS)dotnet-runtime-21

Use the snap install command to install a .NET Runtime snap package. In this example, .NET 5.0 is installed:

Next, register the dotnet command for the system with the snap alias command:

The command is formatted as: sudo snap alias {package}.{command} {alias}. You can choose any {alias} name you would like. For example, you could name the command after the specific version installed by snap: sudo snap alias dotnet-runtime-50.dotnet dotnet50. When you use the command dotnet50, you'll invoke a specific version of .NET. But choosing a different alias is incompatible with most tutorials and examples as they expect a dotnet command to be available.

Export the install location

The DOTNET_ROOT environment variable is often used by tools to determine where .NET is installed. When .NET is installed through Snap, this environment variable isn't configured. You should configure the DOTNET_ROOT environment variable in your profile. The path to the snap uses the following format: /snap/{package}/current. For example, if you installed the dotnet-sdk snap, use the following command to set the environment variable to where .NET is located:

Tip

Install Docker Snaps

The preceding export command only sets the environment variable for the terminal session in which it was run.

You can edit your shell profile to permanently add the commands. There are a number of different shells available for Linux and each has a different profile. For example:

  • Bash Shell: ~/.bash_profile, ~/.bashrc
  • Korn Shell: ~/.kshrc or .profile
  • Z Shell: ~/.zshrc or .zprofile

Edit the appropriate source file for your shell and add export DOTNET_ROOT=/snap/dotnet-sdk/current.

Docker

TLS/SSL Certificate errors

When .NET is installed through Snap, it's possible that on some distros the .NET TLS/SSL certificates may not be found and you may receive an error during restore:

To resolve this problem, set a few environment variables:

The certificate location will vary by distro. Here are the locations for the distros where the issue has been experienced.

DistributionLocation
Fedora/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem
OpenSUSE/etc/ssl/ca-bundle.pem
Solus/etc/ssl/certs/ca-certificates.crt

Troubles resolving dotnet

It's common for other apps, such as the OmniSharp extension for Visual Studio Code, to try to resolve the location of the .NET SDK. Typically, this is done by figuring out where the dotnet executable is located. A snap-installed .NET SDK may confuse these apps. When these apps can't resolve the .NET SDK, you'll see an error similar to one of the following messages:

  • The SDK 'Microsoft.NET.Sdk' specified could not be found
  • The SDK 'Microsoft.NET.Sdk.Web' specified could not be found
  • The SDK 'Microsoft.NET.Sdk.Razor' specified could not be found

To fix this problem, symlink the snap dotnet executable to the location that the program is looking for. Two common paths the dotnet command is looking for are /usr/local/bin/dotnet and /usr/share/dotnet. For example, to link the current .NET SDK snap package, use the following command:

You can also review these GitHub issues for information about these problems:

The dotnet alias

It's possible that if you created the dotnet alias for the snap-installed .NET, you'll have a conflict. Use the snap unalias dotnet command to remove it, and then add a different alias if you want.

Install Docker Snap

Next steps

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