AKS Periscope

Quick troubleshooting for your Azure Kubernetes Service (AKS) cluster.

Overview

Hopefully most of the time, your AKS cluster is running happily and healthy. However, when things do go wrong, AKS customers need a tool to help them diagnose and collect the logs necessary to troubleshoot the issue. It can be difficult to collect the appropriate node and pod logs to figure what's wrong, how to fix the problem, or even to pass on those logs to others to help.

AKS Periscope allows AKS customers to run initial diagnostics and collect and export the logs (such as into an Azure Blob storage account) to help them analyze and identify potential problems or easily share the information to support to help with the troubleshooting process with a simple az aks kollect command. These cluster issues are often caused by incorrect cluster configuration, such as networking or permission issues. This tool will allow AKS customers to run initial diagnostics and collect logs and custom analyses that helps them identify the underlying problems.

Raw Logs and metrics from an AKS cluster are collected and basic diagnostic signals are generated by analyzing these raw data. More advanced diagnostic signals can be further generated by analyzing multiple basic diagnostic signals.

Data Privacy and Collection

AKS Periscope runs on customer's agent pool nodes and collects VM and container level data. It is important that the customer is aware and gives consent before the tool is deployed/information shared. Microsoft guidelines can be found in the link below:

https://azure.microsoft.com/en-us/support/legal/support-diagnostic-information-collection/

Compatibility

AKS Periscope can run on both Linux and Windows nodes, but there are some functional differences between Windows and Linux behaviour.

Current Feature Set

Periscope collects the following logs and metrics:

1. Container logs (by default all containers in the kube-system namespace. Can be configured to take other namespace/containers).
2. Docker and Kubelet system service logs.
3. Network outbound connectivity, include checks for internet, API server, Tunnel, Azure Container Registry and Microsoft Container Registry.
4. Node IP Tables.
5. All node level logs (by default cluster provision log and cloud init log. Can be configured to take other logs).
6. VM and Kubernetes cluster level DNS settings.
7. Describe Kubernetes objects (by default all pods/services/deployments in the kube-system namespace. Can be configured to take other namespace/objects).
8. Kubelet command arguments.
9. System performance (kubectl top nodes and kubectl top pods).

It also generates the following diagnostic signals:

1. Network outbound connectivity, reports the down period for a specific connection.
2. Network configuration, includes Network Plugin, DNS, and Max Pods per Node settings.

User Guide

AKS Periscope can be deployed by using Azure Command-Line tool (CLI). The steps are:

1. If CLI extension aks-preview has been installed previously, uninstall it first.

sh az extension remove --name aks-preview

1. Install CLI extension aks-preview.

sh az extension add --name aks-preview

1. Run az aks kollect command to collect metrics and diagnostic information, and upload to an Azure storage account. Use az aks kollect -h to check command details. Some useful examples are also listed below:

2. Using storage account name and a shared access signature token with write permission

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster \ --storage-account MyStorageAccount \ --sas-token "MySasToken"

3. Using the resource id of a storage account resource you own.

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster \ --storage-account "MyStorageAccountResourceId"

4. Using a pre-setup storage account in diagnostics settings for your managed cluster.

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster

5. Customize the container logs to collect. Its value can be either all containers in a namespace, for example, kube-system, or a specific container in a namespace, for example, kube-system/tunnelfront.

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster \ --container-logs "mynamespace1/mypod1 myns2"

6. Customize the kubernetes objects to collect. Its value can be either all objects of a type in a namespace, for example, kube-system/pod, or a specific object of a type in a namespace, for example, kube-system/deployment/tunnelfront.

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster \ --kube-objects "mynamespace1/service myns2/deployment/deployment1"

7. Customize the node log files to collect.

   sh az aks kollect \ -g MyResourceGroup \ -n MyManagedCluster \ --node-logs "/var/log/azure-vnet.log /var/log/azure-vnet-ipam.log"

All collected logs, metrics and node level diagnostic information is stored on host nodes under directory:

/var/log/aks-periscope.

This directory is also mounted to container as:

/aks-periscope.

After export, they will also be stored in Azure Blob Storage in a container named with the cluster's API Server FQDN. A zip file is also created for easy download.

Alternatively, AKS Periscope can be deployed directly with kubectl. See instructions in Appendix.

Programming Guide

To locally build this project from the root of this repository:

CGO_ENABLED=0 GOOS=linux go build -mod=vendor github.com/Azure/aks-periscope/cmd/aks-periscope

Automated Tests

See this guide for running automated tests in a CI or development environment.

Tip: To test local changes, there are instructions for running Periscope in a Kind cluster in the 'dev' Kustomize overlay notes. This allows for altering the configuration without touching any source-controlled files.

Tip: To test changes in a GitHub branch, there are instructions for running images published to a local GHCR registry in the 'dynamic-image' Kustomize overlay notes.This is especially useful for verifying Windows images.

Dependent Consuming Tools and Working Contract

Dependent tools need access to an immutable, versioned Periscope resource definition. We provide two ways to obtain this: 1. [Deprecated] Build the external overlay using instructions here and include the output as a static resource in consuming tools. This will require runtime string substitution to configure appropriately for any given deployment, before being deployed using kubectl -f. 2. Build a Kustomize overlay at runtime, referencing https://github.com/azure/aks-periscope//deployment/base?ref={RELEASE_TAG} as the base, and the appropriate MCR image tags for that release, as well as all configuration and secrets. This can then be deployed using kubectl -k. Example:

resources:
- https://github.com/azure/aks-periscope//deployment/base?ref={RELEASE_TAG}
images:
- name: periscope
  newName: mcr.microsoft.com/aks/periscope
  newTag: "{IMAGE_TAG}"
secretGenerator:
- name: azureblob-secret
  behavior: replace
  literals:
  - AZURE_BLOB_ACCOUNT_NAME={STG_ACCOUNT}
  - AZURE_BLOB_SAS_KEY=?{STG_SAS}
  - AZURE_BLOB_CONTAINER_NAME={STG_CONTAINER}
configMapGenerator:
- name: diagnostic-config
  behavior: merge
  literals:
  # Only specify those which should be overridden
  - DIAGNOSTIC_KUBEOBJECTS_LIST={KUBEOBJECTS_OVERRIDE}

Debugging Guide

This section intends to add some tips for debugging pod logs using aks-periscope.

Scenario, where user A uses expired sas-token and converts into base64 to be used in the deployment file.

In the scenario above, the kubectl apply -k ./deployment/overlays/dev will show no error but the output which will look like the one below.

❯ kubectl apply -k ./deployment/overlays/dev
namespace/aks-periscope created
serviceaccount/aks-periscope-service-account created
clusterrole.rbac.authorization.k8s.io/aks-periscope-role unchanged
clusterrolebinding.rbac.authorization.k8s.io/aks-periscope-role-binding unchanged
clusterrolebinding.rbac.authorization.k8s.io/aks-periscope-role-binding-view unchanged
daemonset.apps/aks-periscope created
secret/azureblob-secret created
configmap/diagnostic-config created
customresourcedefinition.apiextensions.k8s.io/diagnostics.aks-periscope.azure.github.com unchanged

To debug the pod logs in the aks-periscope-dev namespace deployed in the cluster:

• To get the pods in aks-periscope-dev namespace:
  • kubectl get pods -n aks-periscope-dev
• To check the logs in each of the deployed pods:
  • kubectl logs <name-of-pod> -n aks-periscope-dev

Feel free to contact aksperiscope@microsoft.com or open an issue with any feedback or questions about AKS Periscope. This is currently a work in progress, but look out for more capabilities to come!

Contributing

This project welcomes contributions and suggestions. Most contributions require you to agree to a Contributor License Agreement (CLA) declaring that you have the right to, and actually do, grant us the rights to use your contribution. For details, visit https://cla.opensource.microsoft.com.

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This project has adopted the Microsoft Open Source Code of Conduct. For more information see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.