Installing kubernetes and databases on VMs with ansible


In a production environment, some parts of the wire-server infrastructure (such as e.g. cassandra databases) are best configured outside kubernetes. Additionally, kubernetes can be rapidly set up with kubespray, via ansible. This section covers installing VMs with ansible.


  • A bare-metal setup (no cloud provider)

  • All machines run ubuntu 18.04

  • All machines have static IP addresses

  • Time on all machines is being kept in sync

  • You have the following virtual machines:



CPU Cores

Memory (GB)

Disk Space (GB)

























Per-Server Totals

11 CPU Cores

18 GB Memory

590 GB Disk Space

Admin Host²





Asset Host²





Per-Server Totals with Admin and Asset Hosts

13 CPU Cores

26 GB Memory

730 GB Disk Space

  • ¹ Kubernetes hosts may need more ressources to support SFT (Conference Calling). See “Conference Calling Hardware Requirements” below.

  • ² Admin and Asset Hosts can run on any one of the 3 servers, but that server must not allocate additional resources as indicated in the table above.

  • ³ Etcd is run inside of Kubernetes, hence no specific resource allocation

  • ⁴ Restund may be hosted on only 2 of the 3 servers, or all 3. Two nodes are enough to ensure high availability of Restund services

General Hardware Requirements

  • Minimum 3 physical servers required

  • Wire has a minimum requirement for a total of 16 Ubuntu 18.04 virtual machines across the 3 servers (in accordance with the table above)

Conference Calling Hardware Requirements

  • Kubernetes Hosts may need additional resources for SFT services. For concurrent SFT users (SFT = Selective Forwarding Turn-server, ie. Conference calling), we recommend an extra 3% of CPU allocation, evenly distributed across the nodes (i.e. 1% more CPU per kubernetes server). So for every 100 users plan on adding one CPU core on each Kubernetes node. The SFT component runs inside of Kubernetes, and does not require a separate virtual machine for operation.

(It’s up to you how you create these machines - kvm on a bare metal machine, VM on a cloud provider, real physical machines, etc.)

Preparing to run ansible

Adding IPs to hosts.ini

Go to your checked-out wire-server-deploy/ansible folder:

cd wire-server-deploy/ansible

Copy the example hosts file:

cp hosts.example.ini hosts.ini
  • Edit the hosts.ini, setting the permanent IPs of the hosts you are setting up wire on.

  • On each of the lines declaring a database service node ( lines in the [all] section beginning with cassandra, elasticsearch, or minio) replace the ansible_host values (X.X.X.X) with the IPs of the nodes that you can connect to via SSH. these are the ‘internal’ addresses of the machines, not what a client will be connecting to.

  • On each of the lines declaring a kubernetes node (lines in the [all] section starting with ‘kubenode’) replace the ip values (Y.Y.Y.Y) with the IPs which you wish kubernetes to provide services to clients on, and replace the ansible_host values (X.X.X.X) with the IPs of the nodes that you can connect to via SSH. If the IP you want to provide services on is the same IP that you use to connect, remove the ip=Y.Y.Y.Y completely.

  • On each of the lines declaring an etcd node (lines in the [all] section starting with etcd), use the same values as you used on the coresponding kubenode lines in the prior step.

  • If you are deploying Restund for voice/video services then on each of the lines declaring a restund node (lines in the [all] section beginning with restund), replace the ansible_host values (X.X.X.X) with the IPs of the nodes that you can connect to via SSH.

  • Edit the minio variables in [minio:vars] (prefix, domain and deeplink_title) by replacing with your own domain.

There are more settings in this file that we will set in later steps.


Some of these playbooks mess with the hostnames of their targets. You MUST pick different hosts for playbooks that rename the host. If you e.g. attempt to run Cassandra and k8s on the same 3 machines, the hostnames will be overwritten by the second installation playbook, breaking the first.

At the least, we know that the cassandra, kubernetes and restund playbooks are guilty of hostname manipulation.



If you use ssh keys, and the user you login with is either root or can elevate to root without a password, you don’t need to do anything further to use ansible. If, however, you use password authentication for ssh access, and/or your login user needs a password to become root, see Manage ansible authentication settings.

Running ansible to install software on your machines

You can install kubernetes, cassandra, restund, etc in any order.


In case you only have a single network interface with public IPs but wish to protect inter-database communication, you may use the tinc.yml playbook to create a private network interface. In this case, ensure tinc is setup BEFORE running any other playbook. See tinc

Installing kubernetes

Kubernetes is installed via ansible.

To install kubernetes:

From wire-server-deploy/ansible:

ansible-playbook -i hosts.ini kubernetes.yml -vv

When the playbook finishes correctly (which can take up to 20 minutes), you should have a folder artifacts containing a file admin.conf. Copy this file:

mkdir -p ~/.kube
cp artifacts/admin.conf ~/.kube/config

Make sure you can reach the server:

kubectl version

should give output similar to this:

Client Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.7", GitCommit:"1dd5338295409edcfff11505e7bb246f0d325d15", GitTreeState:"clean", BuildDate:"2021-01-13T13:23:52Z", GoVersion:"go1.15.5", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.7", GitCommit:"1dd5338295409edcfff11505e7bb246f0d325d15", GitTreeState:"clean", BuildDate:"2021-01-13T13:15:20Z", GoVersion:"go1.15.5", Compiler:"gc", Platform:"linux/amd64"}


  • If you would like to change the name of the cluster, in your ‘hosts.ini’ file, in the [cassandra:vars] section, uncomment the line that changes ‘cassandra_clustername’, and change default to be the name you want the cluster to have.

  • If you want cassandra nodes to talk to each other on a specific network interface, rather than the one you use to connect via SSH, In your ‘hosts.ini’ file, in the [all:vars] section, uncomment, and set ‘cassandra_network_interface’ to the name of the ethernet interface you want cassandra nodes to talk to each other on. For example:

# cassandra_clustername: default

## set to True if using AWS
is_aws_environment = False
## Set the network interface name for cassandra to bind to if you have more than one network interface
cassandra_network_interface = eth0

(see defaults/main.yml for a full list of variables to change if necessary)

  • Use ansible to deploy Cassandra:

ansible-playbook -i hosts.ini cassandra.yml -vv


  • In your ‘hosts.ini’ file, in the [all:vars] section, uncomment and set ‘elasticsearch_network_interface’ to the name of the interface you want elasticsearch nodes to talk to each other on.

  • If you are performing an offline install, or for some other reason are using an APT mirror other than the default to retrieve elasticsearch-oss packages from, you need to specify that mirror by setting ‘es_apt_key’ and ‘es_apt_url’ in the [all:vars] section of your hosts.ini file.

# default first interface on ubuntu on kvm:

## Set these in order to use an APT mirror other than the default.
# es_apt_key = "https://<mymirror>/linux/ubuntu/gpg"
# es_apt_url = "deb [trusted=yes] https://<mymirror>/apt bionic stable"
  • Use ansible and deploy ElasticSearch:

ansible-playbook -i hosts.ini elasticsearch.yml -vv


Minio is used for asset storage, in the case that you are not running on AWS infrastructure, or feel uncomfortable storing assets in S3 in encrypted form. If you are using S3 instead of Minio, skip this step.

  • In your ‘hosts.ini’ file, in the [all:vars] section, make sure you set the ‘minio_network_interface’ to the name of the interface you want minio nodes to talk to each other on. The default from the playbook is not going to be correct for your machine. For example:

  • In your ‘hosts.ini’ file, in the [minio:vars] section, ensure you set minio_access_key and minio_secret key.

  • If you intend to use a deep link to configure your clients to talk to the backend, you need to specify your domain (and optionally your prefix), so that links to your deep link json file are generated correctly. By configuring these values, you fill in the blanks of https://{{ prefix }}assets.{{ domain }}.

# if you want to use deep links for client configuration:
#minio_deeplink_prefix = ""
#minio_deeplink_domain = ""

# Default first interface on ubuntu on kvm:
  • Use ansible, and deploy Minio:

ansible-playbook -i hosts.ini minio.yml -vv


For instructions on how to install Restund, see this page.


After running the above playbooks, it is important to ensure that everything is setup correctly. Please have a look at the post install checks in the section Verifying your installation

ansible-playbook -i hosts.ini cassandra-verify-ntp.yml -vv

Installing helm charts - prerequisites

The helm_external.yml playbook is used to write or update the IPs of the databases servers in the values/<database>-external/values.yaml files, and thus make them available for helm and the <database>-external charts (e.g. cassandra-external, elasticsearch-external, etc).

Due to limitations in the playbook, make sure that you have defined the network interfaces for each of the database services in your hosts.ini, even if they are running on the same interface that you connect to via SSH. In your hosts.ini under [all:vars]:

minio_network_interface = ...
cassandra_network_interface = ...
elasticsearch_network_interface = ...
# if you're using redis external...
redis_network_interface = ...

Now run the helm_external.yml playbook, to populate network values for helm:

ansible-playbook -i hosts.ini -vv --diff helm_external.yml

You can now can install the helm charts.

Next steps for high-available production installation

Your next step will be Installing wire-server (production) components using Helm