LeApp is a "Minimum Viable Migration" utility that aims to decouple virtualized applications from the operating system kernel included in their VM image by migrating them into macrocontainers that include all of the traditional components of a stateful VM (operating system user space, application runtime, management tools, configuration files, etc), but use the kernel of the container host rather than providing their own.
The migration prototype currently handles exactly two cases:
- migrating from a CentOS 6 VM to a macrocontainer running on a CentOS 7 container host.
- migrating from a CentOS 7 VM to a macrocontainer running on a CentOS 7 container host.
If the integration tests haven't been run, first install the testing instance of the CLI:
$ pipsi --bin-dir $PWD/bin install --python `which python2.7` $PWD/src
The integration tests do this automatically, so this step can be skipped if those have already been run.
GCC is needed to compile vagrant plugins
$ sudo yum install qemu libguestfs-tools-c libvirt libvirt-devel ruby-devel gcc qemu-kvm nmap libffi-devel
The prototype requires Vagrant with some relevant plugins:
$ sudo vagrant plugin install ansible hitimes nio4r vagrant-libvirt
And passwordless access to VM management operations:
$ sudo usermod -aG vagrant,libvirt $USER
You will need to log out and back in again, or start a new user
session with su $USER, to get the new group memberships to take
effect.
Finally, start all the demonstration VMs by running:
$ demo/start_vms.sh
This script iterates over all the subdirectories of demo/vmdefs and runs
vagrant up --provision.
First, check that the source VM is showing the PHP admin login page at port 9000, while the target VM isn't running a HTTP server.
The demo admin login credentials are:
- Username:
root - Password:
toor
Then, from the base of the local clone, run:
$ sudo bin/leapp-tool migrate-machine \
--identity integration-tests/config/leappto_testing_key \
--tcp-port 9000:9000 -t centos7-target centos6-app-vm
The target VM should now be showing the PHP admin page, with the same information as the source VM.
Link the Cockpit plugin (if not already linked):
$ mkdir -p ~/.local/share/cockpit
$ ln -snf $PWD/cockpit ~/.local/share/cockpit/leapp
Link the leapp project directory (if not already linked):
$ sudo ln -snf $PWD /opt/leapp
Open Cockpit in your browser:
http://localhost:9090
When authenticating, check the option to allow Cockpit to retain your password for later privilege escalation.
Open "Tools->Le-App" from the navigation menu.
Check that the application link for the source VM show the PHP info page, while the target VM isn't running a HTTP server.
Click the "Migrate" button (this is currently
hardcoded to migrate centos6-app-vm to centos7-target)
The target VM should now be showing the PHP info page, with the same information as the source VM.
Currently known constraints on this approach:
- SELinux process separation is not available inside the resulting macrocontainer
Key limitations in the current implementation:
- Remote access to systems requires Vagrant managed VMs running locally under libvirt