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Euphrosyne Reconciler

The Euphrosyne Reconciler is responsible for listening for alerts raised by an alerting system and orchestrating the process of investigating the detected incident, suggesting mitigation actions and eventually executing them. The Reconciler is designed as a K8s-native operator that lives inside the cluster and provides 2 interfaces, one internal to the K8s cluster and one external:

  • /webhook: an internal interface for receiving alerts from the configured monitoring/alerting system
  • /api: an external interface to expose parts of the internal state, as well as the supported actions. More specifically:
    • /api/status: provide details about the workloads responsible for debugging/mitigating an incident
    • /api/actions: execute actions based on the provided data

The basic unit of execution for the Reconciler is a recipe. A recipe is essentially a script, carrying out predefined actions based on its input data. There are 2 types of recipes:

  • Debugging recipes: series of steps for analysing an incident and suggesting a mitigation action. An example recipe could be receiving alert data as input, retrieving metrics from multiple sources, looking for patterns (e.g. failing nodes, user errors, networking issues), and suggesting mitigation actions (e.g. opening a Jira issue describing the incident, starting a Webex discussion, bringing a node offline)
  • Action recipes: series of steps responsible for carrying out the actions suggested by the debugging recipes

Each recipe is executed as a K8s Job on the cluster. The Euphrosyne Reconciler is responsible for submitting Jobs for execution, waiting for their completion, and aggregating their results. New recipes can be registered through the configured K8s ConfigMap object.

A common workflow looks like this:

  1. The Reconciler receives an alert from the alerting system signifying an incident
  2. The Reconciler retrieves the registered debugging recipes dynamically from the configured ConfigMap
  3. The Reconciler submits each one of the retrieved recipes as a separate K8s Job (i.e. the recipes run in parallel)
  4. Each recipe goes through its predefined steps to debug the incident and logs its results upon completion
    • A recipe might be successful (managed to identify the problem) or not
  5. The Reconciler collects the results from the completed recipes and aggregates them
  6. The Reconciler sends the analysis and suggested mitigation actions as generated by the recipes to a configured Webex Bot
    • The Webex Bot is a possible way of interfacing with human operators
  7. A human operator receives a message from the Webex Bot in their chat, inspects the analysis, and approves the suggested action(s)
  8. The Webex Bot sends the approved action(s) back to the Reconciler through its /api/actions interface
  9. The Reconciler retrieves the registered action recipes dynamically from the configured ConfigMap
  10. The Reconciler submits the recipes that correspond to the requested action(s) to be executed as K8s Job(s) (i.e. the recipes run in parallel)
  11. Each recipe goes through its predefined steps to carry out the intended action and logs its results upon completion
  12. The Reconciler collects the results from the completed recipes and aggregates them
  13. The Reconciler sends the outcome of the actions to the configured Webex Bot

It's worth noting that the collection of the recipe results is implemented using Redis, along with a Pub/Sub model that allows the Reconciler to await the results of the submitted recipes.

Setup

In order to setup the Euphrosyne Reconciler you will need a working Kubernetes cluster and kubectl configured to communicate with the API Server. An easy way to get started is microk8s.

To apply the Kubernetes manifests responsible for setting up the Reconciler on Kubernetes, run the following (recursively applying all YAML files inside the manifests directory). If no namespace is specified, these will be deployed in the configured default namespace:

kubectl apply -f reconciler/manifests -R

If you wish to deploy the Reconciler in a different namespace you'll have to update the Redis address accordingly before applying the manifests (replacing <reconciler-namespace> with your desired namespace):

sed -i /euphrosyne-reconciler-redis.default.svc.cluster.local/s/default/<reconciler-namespace>/g \
  reconciler/manifests/deployment.yaml

You will also need to apply the ConfigMap containing the list of available recipes. If no namespace is specified, this will be deployed in the configured default namespace:

kubectl apply -f recipes/kubernetes/orpheus-operator-recipes.yaml

Configuring Kubernetes Secrets

In order for the Euphrosyne Reconciler to be able to interact with external services, we load the corresponding credentials from Kubernetes secrets. Please run the following command, providing your own credentials for accessing Jira. If no namespace is specified this will be created in the configured default namespace:

kubectl create secret generic euphrosyne-keys \
  --from-literal=jira-url=<your Jira server URL> \
  --from-literal=jira-user=<your Jira username> \
  --from-literal=jira-token=<your Jira token>

Configuring a different namespace for executing recipes

By default, recipes are created and run in the same namespace where the Reconciler is deployed, which might not be desired, due to security implications. In order to successfully configure the Reconciler to run recipes elsewhere, you need to ensure that it has the necessary permissions in the target recipe. The first step is to create the required Role and RoleBinding. You will have to edit the command below replacing <recipe-namespace> and <reconciler-namespace> with the actual namespaces:

kubectl apply -f - -n <recipe-namespace> <<EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  labels:
    app: orpheus-operator
    component: euphrosyne-reconciler
  name: euphrosyne-reconciler-recipes
rules:
- apiGroups:
  - ""
  resources:
  - configmaps
  verbs:
  - create
  - deletecollection
- apiGroups:
  - "batch"
  resources:
  - jobs
  verbs:
  - get
  - list
  - create
  - deletecollection
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  labels:
    app: orpheus-operator
    component: euphrosyne-reconciler
  name: euphrosyne-reconciler-recipes
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: euphrosyne-reconciler-recipes
subjects:
- kind: ServiceAccount
  name: euphrosyne-reconciler
  namespace: <reconciler-namespace>
EOF

Subsequently, you'll have to edit the deployment manifest specifying the <recipe-namespace>:

--- a/reconciler/manifests/deployment.yaml
+++ b/reconciler/manifests/deployment.yaml
@@ -31,6 +31,8 @@ spec:
             - euphrosyne-reconciler-redis.default.svc.cluster.local:80
             - --recipe-timeout
             - "300"
+            - --recipe-namespace
+            - <recipe-namespace>
           ports:
             - containerPort: 8080
             - containerPort: 8081

Finally, you'll have to apply the Deployment again (or all of the manifests if you haven't done so already), as well as the Secret, replacing <recipe-namespace> and <reconciler-namespace> with the actual namespaces:

sed -i /euphrosyne-reconciler-redis.default.svc.cluster.local/s/default/<reconciler-namespace>/g \
  reconciler/manifests/deployment.yaml
kubectl apply -f reconciler/manifests -R -n <reconciler-namespace>
kubectl apply -f recipes/kubernetes/orpheus-operator-recipes.yaml -n <reconciler-namespace>
kubectl create secret generic euphrosyne-keys \
  --from-literal=jira-url=<your Jira server URL> \
  --from-literal=jira-user=<your Jira username> \
  --from-literal=jira-token=<your Jira token> \
  -n <recipe-namespace>