There is a nice site to start learning Linux: This is Arch wiki. In fact, an interesting thing to do is starting by installing Arch linux following Arch’s wiki installation guide. Of course, I wouldn’t recommend doing this on your laptop hardware, but I would rather recommend installing it using a virtual machine first, until you feel comfortable with your Arch Lilnux installation.
In this case, as I’m a linux user, I’ll create a new VM using KVM with the help or virt-manager, which is faster than VirtualBox. However, Virtualbox has a clear advantage over KVM: You can use it in Windows, MacOS and of course, in Linux.
Creating the Virtual Machine
You can download the ISO image following the instructions in their download page. You can also create your Virtual server using virt-manager (or the way you prefer it). You should properly configure your virtual hardware (in my case I’ll use 8Gb Ram and 4 CPU cores and a new 60Gb hard disk, which is far more than needed).
The CPU configuration for my VM will use a host-passthrough for my host configuration. This will be quite performant and will allow me to use nested virtualization whenever I want to use it… And I’m sure I’ll want to use it a some point in the future.
In order to get good enough performance with the video driver without bloating the CPU usage in the physical host, I’ll configure:
Starting my Arch Linux VM and Installation
Once we have everything configured, we start our virtual server and start Installation. The important thing here is read and understand the wiki’s installation guide.
# Load keymap -- Default is "US". Mine is "es"... Use yours
# Verify your IP link
# Mine is enp1s0 -- so, I'll get my IP
# Update date
timedatectl set-ntp true
Now one very important part: partitioning disks. In my case, as I’m using KVM, my disk is “named” as /dev/vda, This is the one where I need to make the partitions with fdisk. I’ll do it the simplest way this time:
After the partition, we must type a few commands to do the actual installation
# Format the partition
mkfs -t ext4 /dev/vda1
# Mount the partition in /mnt
mount /dev/vda1 /mnt
# Install the essential packages (and other useful packages)
pacstrap /mnt base base-devel linux linux-firmware grub neovim nano sudo git
# Generate the fstab file
genfstab -U /mnt >> /mnt/etc/fstab
# Change the root directory to /mnt to continue the installation.
# Configure the timezone (mine is Madrid)
# ln -sf /usr/share/zoneinfo/Region/City /etc/localtime
ln -sf /usr/share/zoneinfo/Europe/Madrid /etc/localtime
# Run hwclock(8) to generate /etc/adjtime:
# Edit /etc/locale.gen and uncomment needed locales.... This can be usim nvim
# or using nano
sed -i 's|#en_US.UTF|en_US.UTF|g' /etc/locale.gen
sed -i 's|#es_ES.UTF|es_ES.UTF|g' /etc/locale.gen
# generate locales
# Configure LANG variable in locale.conf
echo "LANG=es_ES.UTF-8" > /etc/locale.conf
# Configure Console keys
echo "KEYMAP=es" > /etc/vconsole.conf
# Configure a hostname for the server and /etc/hosts
echo "archi3" > /etc/hostname
# Esto se puede editar con nvim o nano
cat << EOT > /etc/hosts
We should add now a new user and allow it to become root using sudo. Arch Linux suggest the mechanism to do this is allowing the wheel group to become root using sudo, that’s why we need to change /etc/sudoers as follows.
## Uncomment to allow members of group wheel to execute any command
%wheel ALL=(ALL) ALL
It is time to create the user and add it to goup “wheel” so it can become root.
# Create the user
useradd -m jicg
# Add it to the group "wheel", so it can become root
usermod -aG wheel jicg
# Add a new password to jicg
The next step is adding grub loader so the operating system can load in next reboots and enabling NetworkManager service so it boots with a simple Network configuration. One last step: reboot.
You can download it and run it as root. It will install X11 with lighdm, openssh and set the key map to Spanish inside X. So, after running the script we’ll have X-Windows there installed with a very simple greeter (lightdm default greeter):
The first time we start I3WM, it will create a new configuration file. A very simple configuration file. It’ll make us choose what is the “default modifier” key. I thing the Windows key is the one to choose.
In order to be able to do something with i3wm, we must know a couple key bindings:
<win>+<enter> — Opens a terminal
<win>+d — Opens a menu. We can type, for example firefox in order to open a browser
<win>+1,2,3,…, 0 — Changes to a different “desktop”. We have 10 by default.
A final thought
The windows are not in optimal resolution at this time. In order to improve resolution, I would check with xrandr the possibilities
In my case, 1920×1080 will do the job:
xrandr -s 1920x1080
This is a very lightweight operating system. At boot time, with only a terminal, it will less than 140Mb to run:
Recently I wrote a post about deploying Openstack using kolla-ansible. I finished the article explaining that it was working based on the results of Openstack’s dashboard. Yes, I can say that it is working. However, there is not much we can do with an empty installation of Openstack. So, it is working… What should I do as Openstack admin to make it (a bit) useful?
Install Openstack CLI (Command Line Interface) So, the admin can type commands to openstack in the CLI Interface. Everything explained in this article can be done with the Web Console but I think it is more productive to use the Command Line.
Add images to Glance When a Virtual Machine is created (new Instance), the disk of the Instance is built from a previously existent disk image. Something to act as the base for the instance. We need one or more images to build VMs
Add flavors When a new Instance is created, we need to specify its size in terms of Disk, Memory and Virtual CPUs. This is done using Flavors. By default there is no flavor defined:
Create Networks A new instance is not useful if it can’t connect to the internet or we can’t login in the VM. We need to define virtual networks so we can work with our VMs.
Create/Manage users So different users (at least a non-admin user) should work with the Openstack installation.
On the other hand, what shoud I do as an Openstack user to start using virtual hosts in my new Openstack Installation?
Create a Keypair That’s the way to access the Virtual Servers when they are running
Define security group So I can set up my own “firewall” and open the ports I need to install and run the software I want in my VM.
Create a Virtual Machine To deploy a new Instance I need to define some things: The image to use, the Flavor of the VM, the network the VM is connected to, the Security groups applied to the VM and the keypair to access the VM.
The user part is out of the scope of this article, however, I’ll show how these parts are done using the CLI.
Install locally the Openstack CLI
In order to have (almost) full control of Openstack, I’d recommend to install the Openstack CLI. There are many ways to install it, however, in this case we’ll do it using a python virtualenv.
We’ll also have to define a few environment variables. Taking advantage of this, we can activate the virtualenv when loading these variables. In order to do this, I’ve created a file named keystoneIdmLocal (the name is not important at all) whith this content:
So, before using the Openstack commands I simply load these environment using:
At the beginning, after the installation there are no networks defined. We’ll need to create at least 2 networks: An internal network allowing communication between all the Virtual Machines and an external network connected to a router (virtual) to connect the Virtual Machines to the internet.
This network will provide internal communication between virtual machines, access to DHCP internal server and metadata server. It is important to have a network ready. This network will be shared, so all users will be able to use it. You can forget this step and expect every user to create its own network.
Creating a Network means creating the network and at least a Subnet where we will configure the most relevants parameters for the Network:
The parameter –share will make this internal network available for every openstack user. All the VMs will be able to use this network.
The external network will provide Internet access to the Virtual Machines. This is a common way to access the VMs from the Internet or from somewhere outside the Openstack installation. In order to create an external network we can type something like this:
This will create a new external network named ext-net. It will provide IPs from 172.23.16.16 to 172.23.16.254 and it will use 188.8.131.52 as DNS server, 172.23.16.1 as gateway.
Adding a router
Once we have an internal and an external network, we’ll need to connect them so incoming/outgoing data in the external network can flow from and to the internal network.
Basically, the way to communicate 2 different networks is using a router and we need a router (a virtual one) to communicate our internal network with the external one. This is done this way:
# Create a router named rt-ext
openstack router create rt-ext
# Set the external gateway (gateway to the Internet)
openstack router set rt-ext --external-gateway ext-net
# Add the subnet (the internal one)
openstack router add subnet rt-ext sub-int-net
After this last step, the external network an the internal one are connected with this router.
A recap on networking:
We need to create an internal network, an external network and router to link both networks:
However, using the Openstack console we can depict nicely the Network topology we’ve created:
A few commands related to networking
Networking is complex and there are many different things to deal with. Anyway, here are a few commands related to networking which could be useful sometimes (apart from the previously given ones):
# Getting help
openstack help network
openstack help router
openstack help subnet
# Show the Networking Agents. Useful to understand the state
# of the different networking components.
openstack network agent list
# Get a list of the networks
openstack network list
# Get the details of a network
openstack network show <network_id_or_name>
# Delete a network
openstack network delete <network_id_or_name>
# Get a list of subnets
openstack subnet list
# Get a list of subnets belonging to a network
openstack subnet list --network <network_id_or_name>
# Show the details of a subnet
openstack subnet show <subnet_id_or_name>
# Delete a subnetwork
openstack subnet delete <subnet_id_or_name>
# List the routers
openstack router list
# Get the details of a router
openstack router show <router_id_or_name>
# Remove the connection of a subnet with a router
openstack router remove subnet <router> <subnet>
# Remove on router's gateway
openstack router unset --external-gateway <router>
Of course in this case, there are tons more of options to deal with. However, this can give you an overview of the basic commands.
Adding images to Glance
A new Virtual Machine is usually built from a disk image stored in Glance. We need disk images to create virtual machines. The most easy way to get these images is downloading them from the Internet.
There is a really small image very useful for testing which can be downloaded from Internet. The next example shows the 2 steps needed to upload a new image to Glance: downloading the Image and uploading it to glance:
# Getting help
openstack help image
# List images:
openstack image list
# Show details from an image
openstack image show <id_or_name>
# Delete an image
openstack image delete <id_or_name>
# Save a local copy of an image
openstack image save --file local_copy.img <id_or_name>
The “Flavor” is a set of definitions regarding the number of CPUs, the virtual disk size and the memory which can be used by a virtual machine. By default there are no flavors defined in Openstack but we’ll need a flavor to create a new Virtual Machine.
Let’s create a couple of public flavors: A small one with 1Mb of RAM, 1 virtual CPU and 10Gb for the disk size (with name small) and a medium one with 2Gb of RAM, 2 Virtual CPUS and 20Gb for the disk size (with name medium):
# Getting help
openstack help flavor
# Listing of flavors
openstack flavor list
# Show details of a flavor
openstack flavor show <flavor_name_or_id>
# Delete a flavor
openstack flavor delete <flavor_name_or_id>
Adding a new user
We could always work as admin, but this is not usually a best practice. We would like to create new users and new projects to work with Openstack.
The basic rules to keep in mind are:
Resources usually belong to projects
An user has one or more roles in one or more projects.
So, we’ll need to create at least a project, at least one user and assign at least one role to the user in the project.
By default there are some roles defined after Opentstack installation:
So, we create a new project, a new user and assign a role to the user in the project this way:
# 1st we create a new project called jicg_project
openstack project create --domain default jicg_project
# 2nd we create a new user called jicg. In this case
# setting a password. This can be changed in the console.
openstack user create --password mysecretpassword jicg
# 3rd we assign the role "member" to the user jicg
# in the project jicg_project
openstack role add --user jicg --project jicg_project member
Now the user should be able to log in the console:
Nova: Our first virtual machine
Everybody wants to know how to deploy a VM and how to use it. Let’s say that there are 4 mandatory steps after the Administrator has created the flavors, the networks and uploaded some images to work with (an user can usually create their own Images, networks, etc.):
Creating one (or more than one) Security Group with some Security Rules.
Creating a Keypair.
Allocating a Floating IP to the project
Launching our 1st Virtual machine.
The first 3 steps are only mandatory for the 1st VM. The following ones could be created
Creating a Security Group and security rules.
Openstack acts as a closed firewall for the VMs it manages and the user is resposible to create some rules for that firewall thoroughly. For the shake of simplicity I’m going to leave out the meaning of “thoroughly” here.
So, the 1st step is creating a Security Group:
# Create a SG with the name demosecgroup
openstack create security group demosecgroup
Add rules to the security group:
# Open tcp port 22 for everybody (network 0.0.0.0/0)
# for incoming traffic.
openstack security group rule create \
--remote-ip 0.0.0.0/0 \
--protocol tcp \
--dst-port 22 \
# The same can be done for port HTTP (80) and HTTPS (443).
Creating a new Keypair
In order to access the Virtual Machines, we’ll use ssh protocol. Most of the images we can get from the Internet are prepared to allow only ssh connections using a Private-public keypair.
We can generate one easily:
# This makes openstack create a keypair. The output of the
# command is the private key. The public key is stored in
# Opentasck so it can be injected in the VMs.
openstack keypair create demokeypair > demokeypair.pem
As you can see, the content of the file is a private keypair which can be used to login in the VMs. There a few things to consider:
The new file has too many permissions. We have to close a bit more the permissions of the file so we can use it with the command “chmod 400 demokeypair.pem“.
If we loose this file, we probably won’t be able to connect to our VMs. There is no way to recover this file.
Allocate a new Public IP.
We have to allocate a new public IP to the project in order to associate it to the VM (when we have a VM). The allocation of a new IP can be done like this:
# ext-net is the name of the external network we created
openstack floating ip create ext-net
We can find the available networks like this
And as you can see, we have a new Floating IP (public IP) which can be shown with command “openstack floating ip list“:
Create our 1st Virtual Host
Finally, this long expected thing!!!. In this step everything done until now makes sense. In order to create a new VM we need to merge all the things we’ve done before in a single command: The image, the shared (internal) network, the security group, the floating IP, the keypair, … Everything!
# Create a new Server which name is demovm
# Using flavor small, from cirros image, using sec. group
# demosecgroup the network internal and the keypair.
# Everything previously created
openstack server create \
--flavor small \
--image cirros \
--security-group demosecgroup \
--network internal \
--key-name demokeypair \
After a few minutes we’ll have our VM created:
The last step is setting the floating IP to this server, given a floating IP:
openstack floating ip list
# My floating IP ID=b43f4537-d28b-4444-a2db-3467500c1900
openstack server add floating ip demovm \
Once done this, I can ssh to my new VM!!!
Caveat: In modern Linuxes the key exchange algorithm will be disabled and thus we’ll be able to login our Cirros VM unless we activate it. We can activate it for this VM editing the file ~/.ssh/config and adding:
# Show the console of the VM (the boot output, basically)
openstack console log show <server_name_or_id>
# Get an URL to connect the VM In the browser.
openstack console url show <server_name_or_id>
Finally, I’d like to show the new network topology with the VM connected to the internal network:
A few commands for Servers
At least there are a few commands we should know in order to work with our Virtual Machines (servers) quickly:
# Getting help
openstack help server
# Shutdown a server
openstack server stop <server_id_or_name>
# Restart a server
openstack server start <server_id_or_name>
# Pause / unapuse a server
openstack server pause <server_id_or_name>
openstack server unpause <server_id_or_name>
# Suspend / resume a server
openstack server suspend <server_id_or_name>
openstack server resume <server_id_or_name>
# Delete a server (Forever! Destroy everything)
openstack server delete <server_id_or_name>
After writing about using LXC and showing its capabilities to run Docker and Virtual Machines, in a Post showing how to start with LXC, and the second one showing how to deploy a Kubernetes cluster in with LXC, I’m going to show today how I’ve deployed an Openstack Cluster using LXC, once more I’ll be using ansible as a helper tool to deploy the containers and install the software I’ll need to deploy in the cluster before deploying Openstack.
As I already said in my previous post, I’ll recomend you to be aware that THIS IS NOT A PRODUCTION SOLUTION. IT IS REALLY UNSECURE. IT IS ONLY INTENDED TO SIMULATE INFRASTRUCUTRE.
Before doing anything, just starting my Ubuntu 20.04 with my Brave Browser to start writing this POST, my memory consumption is 2.62 Gb.
After starting my Openstack cluster with one controller and 3 compute nodes, my memory consumption is 8.4Gb. Yes, it is not cheap in terms of memory, however, it is rather affordable. You can always do with 1 compute node anyway.
As you can imagine, this is going to be a very simple Openstack deployment. Only with a few basic services: Nova (to deploy VMs), Neutron (to manage networks), Glance (for the VM images) and Keystone (for user identification). Maybe in a future I’ll write about deploying more services to this Openstack installation like Cinder to manage volumes or Ceilometer for Telemetry. But in this case it is going to be a very basic deployment.
Installing previous software in my server
Please, keep in mind that “My Server” is nothing but my own laptop. A HP Pavillion with Ubuntu 20.04 installed: Intel i7 with 16Gb RAM and 512Gb Hd.
First of all, I must have ansible installed, however, I already explained that in my POST about Kubernetes on LXC. Anyway, it is only a few lines, so I can write that again:
# To install LXC:
sudo apt install lxc lxc-utils lxc- templates lxc-dev
# To install other packages needed:
sudo apt install python3-lxc virtualenv sshpass bridge-utils
# Create the Virtual environment for ansible:
virtualenv -p python3 ~/.venv/ansible
# To install Ansible.
pip install ansible
As I’ll be using Kolla to deploy Openstack in this installation, I’ll install also in my Virtual Environment kolla-ansible (kolla-ansible==8.1.1 kolla-ansible==8.2.0 — I’ve chosen Stein version in this demo) and the Openstack CLI tools to be able to manage the Openstack Installation:
# Using the Virtual Environment from previous step:
pip install kolla-ansible==8.2.0 python-openstackclient
# The next is the new line to insert...
Caveat: Kolla-ansible doesn’t support Ubuntu 20.04. So, the containers must be Ubuntu 18.04. I’ll recomend you creating a first container manually before running these ansible playbooks because LXC downloads the base container and it installs the software using some kind of normal installation. The command is this one:
sudo lxc-create -t ubuntu -n u1 -- -r bionic
Whilst the lxc-create is running and downloading the Ubuntu packages, you can see that apt is running:
And at a certain point of the installation, it will make you questions that you’ll need to answer. If this is done for the first time using ansible, you won’t have any way to respond these questions and the installation will be stuck forever and it will never end.
Once deployed for the first time, the container will be in Cache and you won’t need to respond these questions again. So, you can answer “yes” this time and when it finish, you can destroy the container:
So, the big box is my server. Inside it there are 4 LXC containers connected to 2 bridges (I’ll create them in the installation). The Br-os bridge is intended as internal communication between the Openstack nodes. The br-ext bridge is intended for the communication of external VMs to the Internet. I’ve decided not to create VLANs or any other Isolation between the different networks for simplicity. However, in a production environment using real servers, these networks should be isolated for security (to prevent VMs from connecting to the Compute or Controller nodes.
The containers will be connected to the bridge br-ext using eth1 and this interface will have no IP configured. The Containers will be connected to the bridge br-os using eth2 and they’ll have an IP here in 172.23.32.0/24.
In order to create the containers, the ansible playbook named CreateLxcContainers.yaml must be run.
This playbook ensures the 2 bridges are created, they are up and they have their corresponding IP. Despite of this, it ensures a few modules are loaded, because they’ll be needed whether for ansible-kolla deployment or for the containers to run properly: – ebtables (required in ansible-kolla deployment) – tap (required in the containers to implement a proper network) – ip_vs (required in ansible-kolla deployment)
iptables -t nat -D POSTROUTING -s 172.23.16.0/24 ! -d 172.23.16.0/24 -j MASQUERADE || true
brctl addbr br-os || true
brctl addbr br-ext || true
ip addr add 172.23.16.1/24 dev br-ext || true
ip addr add 172.23.32.1/24 dev br-os || true
ip link set br-os up
ip link set br-ext up
iptables -t nat -A POSTROUTING -s 172.23.16.0/24 ! -d 172.23.16.0/24 -j MASQUERADE
After this configuration, it deploys the containers and some packets we’ll need for ansible-kolla deployment. You can see the file code in the Github repo mentioned above.
Preparing the containers
Once the containers are running, we must install some software in them to make them ready for Openstack. This is done with the playbook PrepareContainers.yml.
This playbook creates the user/group kolla and add it to the sudoers file. It adds an authorized ssh public key to ~kolla/.ssh/authorized_keys (this must be configured in file playbook/vars/containers.yaml, in the variable public_key. It is not configured with any default key.
The palybook also sets a netplan to configure networking in the container and restart the network and adds some packages that kolla installation will need.
The playbook will set up a new service which will run before the docker service starts in the LXC Container when the container boots. The service will run a script named shared-run.sh:
Make the /run directory as shared (this is needed by Kolla dockers)
Creates /dev/net/tun character device, which will provide better network performance.
Creates /dev/kvm character device so Virtual Machines can be created using KVM (instead of QEMU — emulated virtualization, much slower)
Creates /dev/vhost-net characer device to be able to create virtual networks and let the VMs to communicate between them.
Kolla-Ansible: The installation.
The installation of Kolla-Ansible is described here. However, I’m going to provide the steps in order repeat the installation I did.
As I explained before, I installed kolla ansible (Openstack Stein) in the ansible’s virtual environment. You can find kolla-ansible version here.
pip install kolla-ansible==8.1.1
First of all, we need to create the directory /etc/kolla where kolla-ansible configuration files are stored. However, I simply will create a link this way from the KollaAnsibleOnLXC directory that I’ve previously downloaded from github:
The next step is generating the Passwords for the installation (I’ve provided the passwords that I got once in one installation, but you should generate new passwords for your self). This step will overwrite the file /etc/kolla/passwords.yml with randomly generated passwords.
The inventory file is needed to deploy Openstack using Kolla. Of course, we must edit it before deploying Openstack. In the repository it is already provided an inventory file named multinode. It is tuned for the IPs I’m using in this demo deployment.
# These hostname must be resolvable from your deployment host
172.23.32.2 ansible_user=kolla ansible_become=true
# The above can also be specified as follows:
# The network nodes are where your l3-agent and loadbalancers will run
# This can be the same as a host in the control group
172.23.32.2 ansible_user=kolla ansible_become=true
172.23.32.5 ansible_user=kolla ansible_become=true
172.23.32.6 ansible_user=kolla ansible_become=true
172.23.32.7 ansible_user=kolla ansible_become=true
Kolla’s Configuration File
Now, we must consider reading and understanding the file /etc/kolla/globals.yml. In this file we’ll describe the deployment values that we want to configure for our Openstack deployment. A file tuned for our demo installation is provided in the code you could download from Git Hub.
I’m not going to describe all the parameters I used, but, at least I will describe a few parameters. Let’s start with our network interfaces:
All LXC Containers are connected in the same way to the bridges. The interface eth2 will be used for “management” and it is connected to the bridge I named br-os. They’ll have an in the network 172.23.32.0/24.
The interface eth1 will be used for the Virtual Machines to connect to the Internet. In this case, this interface is connected to br-ext. No IP Is needed here for any LXC Container. In fact, in this case, it would be enough if only the controller had this network interface.
Another parameter is
Which is a Virtual Interface to be used with ha-proxy. Maybe you can think it is not so interesting, but it is. In this case, no ha-proxy should be needed. But if I don’t use it, one task in kolla-ansible will wait until mariadb is ready in ha-proxy. It’ll never be ready and it will fail.
Other configurations are:
# What version of Openstack we'll be installing and the type of installation
# We'll be using rabbitmq for the communications amongst processes.
# We'll be using LinuxBridge to build networks
# The region name will be this RegionDemo:
# The services we will use are: Keystone, glance, nova, neutron and rabbitmq
# We'll be using KVM for virtualization. Not QEMU (The default one)
Despite all of these configurations, we will add 3 passwords (the problem these passwords are not generated with command kolla-genpwd and they are required to complete the installation:
Anyway, please, take a look to the /etc/kolla/globals.yml file and try to understand it.
Finally, the deployment
There are 3 steps to deploy ansible-kolla:
The first step is bootstrapping the LXC Containers, which is done with command:
kolla-ansible -i multinode bootstrap-servers
The second step is optional. This is used to check if everything is ready to install:
kolla-ansible -i multinode prechecks
And finally the installation. The installation will fail because some configurations can’t be applyed in the containers. There are workarounds for this, although this is not the solution I choose, anyway, you’d only need to add in your /etc/kolla/globals.yaml the line:
However, I’ve modified one kolla-ansible file: ~/.venv/ansible/share/kolla-ansible/ansible/roles/neutron/tasks/config.yml ~/.venv/ansible/share/kolla-ansible/ansible/roles/neutron/tasks/config-host.yml adding the line “ignore_errors: yes” at the end of the fist task there:
The fact is that there are things that doesn’t go well, but indeed the task does other things which are useful, I mean, it sets the variables it can set and which are needed, although it can’t set them all. That’s the reason I don’t set the variable “set_sysctl” to false to prevent it from executing. I could have done so and adding the lines to the sysctl.conf in my own playbooks. I preferred this one. Anyway, up to you.
Once this little patch is appliyed, I run the deployment:
kolla-ansible -i multinode deploy
Your Openstack Installation
After the installation, you can start using you new Openstack. First you’ll need to know your admin Password:
Another thing you’ll probably want to do is adding a few lines to your /etc/hosts files. Just for convenience. Please pay attention to the controller IP. Yes, it is the same we added in the configurations for the variable kolla_internal_vip_address
Once done that, you can start your browser to see something or your Openstack installation:
After login you’ll get in a very meaningful screen:
This screen shows the results of some queries done to Openstack in order to get the usage of resource. Openstack services are needed (so they must be properly running) to render this page without errors.
I’ll write soon another POST about what to do with a new and clean Installation of Openstack. This POST has grown long, but I will write a crash course to make your Openstack installation in something which can be used soon.
LXC, as you can read in https://en.wikipedia.org/wiki/LXC, is an operating-system-level virtualization method for running multiple isolated Linux systems (containers) on a control host using a single Linux kernel.
Basically this means that you can have multiple containers behaving as if they were Virtual Machines. This is a different approach to Dockers, which are meant to run a single application inside. For instance, if we wanted to run a WordPress using Docker, we should run a docker for the database and another one for the HTTP server and both Docker should communicate using some networking capabilities. However, if we run the same instance using LXC, we could install the Database and the HTTP server using the same container (a kind of lightweight Virtual Machine). So, I think this is basically the biggest difference: A Docker is thought to run an application and LXC is thought to behave in a close way to a virtual machine.
Installation and first Steps
In order to install LXC we could simply run:
apt install lxc lxc-templates lxc-utils
Now, we can start working with LXC. Of course, the first thing we’d like to do is creating our first LXC Virtual Machine, in order to do this, we could type the following command:
lxc-create -t ubuntu -n u1 -- -r focal
And after a while, we’ll have our container. It won’t be runing, but it will be created. The name of my container, in this case, is n1 In order to run the container we should type:
lxc-start -d -n u1
Once we are running our container, we can see it using the command “lxc-ls –fancy“:
As you can see, when the container is STOPPED, it has no IP. After the container is started, it is assigned an IP address and will use that IP address for the life of the container (until it is destroyed). By default, a bridge is created in LXC host named lxcbr0 which will act as “gateway” for the containers.
NOTE: The default network is 10.0.3.0/24 instead of 10.0.4.0/24 in the example. It doesn’t matter much at this point.
Two other interesting commands to work with containers are: lxc-stop to stop a container and lxc-destroy to definitely remove the container (forever):
# Stop a running container
lxc-stop -n u1
# Remove a stopped container
lxc-destroy -n u1
Configuration of Containers
Once the container is created, a new directory is created in /var/lib/lxc with the name of our container. In our example, the directory will be /var/lib/lxc/u1.
There is a config file in that directory named config. We can change the configuration of the container here. There are plenty of different configurations which can be done here.
The default configuration is enough to run most applications. However, there are some things that might require to change this configuration. For example: Running nested LXC Containers or Dockers, running Virtual Machines using KVM…
If we wanted to run these kind of applications, we must add the following lines to the end of the config file:
lxc.apparmor.profile = unconfined
lxc.cgroup.devices.allow = a
In my example, I’m running LXC in LXC. So this is the reason the IPs of my examples are 10.0.4.0/24 instead of 10.0.3.0/24.
Running Docker inside LXC
I run a new container (this time it won’t be nested):
lxc-create -n docker-in-lxc -t ubuntu
And I add the lines shown above to the end of its config file: /var/lib/lxc/docker-in-lxc/config and I start the container with lxc-start.
I log in the container and I run the command
sudo apt install docker docker.io
Once everything is installed, we can test if it works:
KVM In LXC
Again, we create another lxc container changing its config file as explained above and we can ssh to that container.
Once it gets installed, our libvirt will be there.
Before we can do anything with this, we’ll need to create a device driver which is not present by default in our LXC. The /dev/net/tun which is a must in order to run our Virtual machines with networking:
We also need to be aware that Kernel Modules are not loaded inside the LXC containers. Modules are loaded in the Kernel and the Kernel is shared for every LXC container. So, if we want virtualization to work, we’ll need the KVM Module loaded in the real Linux Kernel: We need kvm installed in our real operating system.
It is not mandatory to have nested virtualization configured in our module. But anyway, I have it.
Once the image is downloaded, I will start a new VM using that image. However, it is a cloud based image which will try to connect to 169.254.169.254 in order to get cloud metadata information. As I don’t have any cloud provider such as openstack, booting a Virtual Machine from this image will take a long, long time. In order to make all this to fail faster, I’m going to add the ip 169.254.169.254 to device eth0 inside the container: