Ansible

Warning: The Ansible installation of a Seldon Core and associated ecosystem is meant for dev/testing purposes. For production use cases follow Helm installation.

Installing Ansible

Provided Ansible playbooks and roles depends on kubernetes.core Ansible Collection for performing kubectl and helm operations. Check Ansible [documentation] for further information.

To install Ansible and required collections

pip install ansible openshift kubernetes docker
ansible-galaxy collection install kubernetes.core

We have tested provided instructions on Python 3.8 - 3.11 with following version of Python libraries

Python	Ansible	Docker	Kubernetes
3.8	6.7.0	6.0.1	26.1.0
3.9	7.2.0	6.0.1	26.1.0
3.10	7.2.0	6.0.1	26.1.0
3.11	7.2.0	6.0.1	26.1.0

and kubernetes.core collection in version 2.4.0.

Once installed you can use the following Playbooks that you will find in Ansible folder of Seldon Core 2 repository.

You also need to have installed kubectl CLI.

Installing Seldon Core 2 using Ansible

One-liner local kind install (from scratch)

If you simply want to install into a fresh local kind k8s cluster, the seldon-all playbook allows you to do so with a single command:

ansible-playbook playbooks/seldon-all.yaml

This will create a Kind cluster and install ecosystem dependencies (kafka, prometheus, opentelemetry, jager) as well as all the seldon-specific components. The seldon components are installed using helm-charts from the current git checkout (../k8s/helm-charts/).

Internally this runs, in order, the following playbooks (described in more detail in the sections below):

• kind-cluster.yaml

• setup-ecosystem.yaml

• setup-seldon.yaml

You may pass any of the additonal variables which are configurable for those playbooks to seldon-all. See the Customizing Ansible Instalation section for details.

For example:

ansible-playbook playbooks/seldon-all.yaml -e seldon_mesh_namespace=my-seldon-mesh -e install_prometheus=no -e @playbooks/vars/set-custom-images.yaml

Running the playbooks individually, as described in the sections below, will give you more control over what gets run and when (for example, if you want to install into an existing k8s cluster).

Create Kind Cluster

It is recommended to first install Seldon Core 2 inside Kind cluster. This allow to test and trial the installation in isolated environment that is easy to remove.

ansible-playbook playbooks/kind-cluster.yaml

Setup Ecosystem

Seldon runs by default in seldon-mesh namespace and a Jaeger pod and and OpenTelemetry collector are installed in the chosen namespace. Run the following:

ansible-playbook playbooks/setup-ecosystem.yaml

The most common change will be to install in another namespace with:

ansible-playbook playbooks/setup-ecosystem.yaml -e seldon_mesh_namespace=<mynamespace>

Install Seldon Core 2

Run the following from the ansible/ folder:

ansible-playbook playbooks/setup-seldon.yaml

If you have changed the namespace you wish to use you will need to run with:

ansible-playbook playbooks/setup-seldon.yaml -e seldon_mesh_namespace=<mynamespace>

Customizing Ansible Installation

Ecosystem configuration options

The ecosystem setup can be parametrized by providing extra Ansible variables, e.g. using -e flag to ansible-playbook command.

For example run the following from the ansible/ folder:

ansible-playbook playbooks/setup-ecosystem.yaml -e full_install=no -e install_kafka=yes

will only install Kafka when setting up the ecosystem.

	type	default	comment
seldon_mesh_namespace	string	seldon-mesh	namespace to install Seldon Core 2
seldon_kafka_namespace	string	seldon-mesh	namespace to install Kafka Cluster for Seldon Core 2
full_install	bool	yes	enables full ecosystem installation
install_kafka	bool	{{ full_install }}	installs Strimzi Kafka Operator
install_prometheus	bool	{{ full_install }}	installs Prometheus Operator
install_grafana	bool	{{ full_install }}	installs Grafana Operator
install_certmanager	bool	{{ full_install }}	installs Cert Manager
install_jaeger	bool	{{ full_install }}	installs Jaeger
install_opentelemetry	bool	{{ full_install }}	installs OpenTelemetry
configure_kafka	bool	{{ install_kafka }}	configures Kafka Cluster for Seldon Core 2
configure_prometheus	bool	{{ install_prometheus }}	configure Prometheus using Seldon Core 2 specific resources
configure_jaeger	bool	{{ install_jaeger }}	configure Jaeger using Seldon Core 2 specific resources
configure_opentelemetry	bool	{{ install_opentelemetry }}	configure OpenTelemetry using Seldon Core 2 specific resources

Seldon Core 2 configuration options

	type	default	comment
seldon_kafka_namespace	string	seldon-mesh	namespace to install Kafka
seldon_mesh_namespace	string	seldon-mesh	namespace to install Seldon
seldon_crds_namespace	string	default	namespace to install Seldon CRDs
full_install	bool	yes	enables full ecosystem installation
install_crds	bool	{{ full_install }}	installs Seldon CRDs
install_components	bool	{{ full_install }}	install Seldon components
install_servers	bool	{{ full_install }}	install Seldon servers

Custom Seldon images and private registries

By default, the container images used in the install are the ones defined by the helm charts (referring to images publicly available on dockerhub).

If you need to customize the images (i.e pull from private registry, pull given tag), create a custom images config file following the example in playbooks/vars/set-custom-images.yaml and run with:

ansible-playbook playbooks/setup-seldon.yaml -e @<path-to-custom-images-config.yaml>

If, instead of pulling images from an external repository you want to build certain components locally, please read README.dev.md

Private registries

When using private registries, access needs to be authenticated (typically, via a service account key), and the k8s cluster will need to have access to a secret holding this key to be able to pull images.

The setup-seldon.yaml playbook will create the required k8s secrets inside the cluster if it is provided with an auth file in dockerconfigjson format. You provide the path to this file by cusomizing the custom_image_pull_secrets.dockerconfigjson variable and define the secret name via custom_image_pull_secrets.name in the custom images config file (the one passed to the playbook via -e @file).

By default, docker creates the dockerconfigjson auth file in ~/.docker/config.json after passing the service-account key to docker login.

The docker login command would look like this (key in json format):

cat registry-sa-key.json | docker login -u _json_key --password-stdin <registry-url>

or, for keys in base64 format:

cat registry-sa-key | docker login -u _json_key_base64 --password-stdin <registry-url>

Saving helm-chart customisations

Because the additional custom images config file (starting from the playbooks/vars/set-custom-images.yaml example) overrides values in the helm-charts available in the repo, there's also a playbook option of saving those overrides as a separate values file, which could be used if deploying manually via helm.

This is controlled via two variables:

	type	default	comment
save_helm_components_overrides	bool	false	enable saving helm values overrides
save_helm_components_overrides_file	string	~/seldon_helm_comp_values.yaml	path/filename for saving overrides

You can either pass those within the custom images config file or directly when running the playbook. For example, for just saving the helm-chart overrides (without installing seldon components), you would run:

ansible-playbook playbooks/setup-seldon.yaml -e full_install=no -e save_helm_components_overrides=yes -e @<path-to-custom-images-config.yaml>

Please note that when deploying outside ansible via helm using this saved overrides file, and using private registries, you will have to manually create the service-account key secret with the same name as the one defined in your custom image config file under custom_image_pull_secrets.name.

Uninstall

To fully remove the Ansible installation delete the created Kind cluster

kind delete cluster --name seldon

This will stop and delete the Kind cluster freeing all of the resources taken by the dev/trial installation. You may want to also remove cache resources used for the installation with

rm -rf ~/.cache/seldon/

If you used Ansible to install Seldon Core 2 and its ecosystem into K8s cluster other than Kind you need to manually remove all the components. Notes on how to remove Seldon Core 2 Helm installation itself you can find here.