Use the event center to monitor cluster anomalies in real time - Container Service for Kubernetes

Event monitoring is a monitoring method provided by Kubernetes. It provides improvements over resource monitoring in terms of timeliness, accuracy, and scenarios. You can use node-problem-detector (NPD) with the Kubernetes event center of Simple Log Service to sink cluster events, and configure NPD to diagnose clusters and send error events to sinks. You can sink cluster events to DingTalk, Simple Log Service, and EventBridge. This allows you to monitor anomalies and issues in clusters in real time.

Billing

By default, the event monitoring feature of ACK sinks cluster events to Simple Log Service. You can store and analyze events in Simple Log Service. The default retention period of ACK cluster events is 90 days. You can store ACK cluster events free of charge for 90 days. For more information, see Create and use an event center.

Background Information

Kubernetes is designed based on the state machine. Events are generated due to transitions between different states. Typically, Normal events are generated when the state machine changes to expected states and Warning events are generated when the state machine changes to unexpected states.

ACK provides out-of-the-box event monitoring solutions that target containerization scenarios. ACK uses NPD and kube-eventer provided by NPD to monitor container events.

NPD is a tool to diagnose Kubernetes nodes. NPD detects node exceptions, generates node events, and works with kube-eventer to raise alerts upon these events and enable closed-loop management of alerts. NPD generates node events when the following exceptions are detected: Docker engine hangs, Linux kernel hangs, outbound traffic exceptions, and file descriptor exceptions. For more information, see NPD.
kube-eventer is an open source event emitter that is maintained by ACK. kube-eventer sends Kubernetes events to sinks such as DingTalk, Simple Log Service, and EventBridge. kube-eventer also provides filter conditions to filter different levels of events. You can use kube-eventer to collect events in real time, trigger alerts upon specific events, and asynchronously archive events. For more information, see kube-eventer.

This topic describes how to configure event monitoring in the following scenarios:

Scenario 1: Use NPD with the Kubernetes event center of Simple Log Service to sink cluster events

NPD works with third-party plug-ins to detect node exceptions and generate cluster events. A Kubernetes cluster also generates events when the status of the cluster changes. For example, when a pod is evicted or an image pull operation fails, a related event is generated. The Kubernetes event center of Simple Log Service collects, stores, and visualizes cluster events. It allows you to query and analyze these events, and configure alerts. You can sink cluster events to the Kubernetes event center of Simple Log Service by using the following methods.

Step 1: Install the ack-node-problem-detector component

If you have selected Install node-problem-detector and Create Event Center when you create the cluster, proceed to Step 2 to view the Kubernetes event center. For more information about how to install the ack-node-problem-detector component when you create a cluster, see Create an ACK managed cluster.
If you did not select Install node-problem-detector and Create Event Center when you create the cluster, perform the following steps to manually install it.
1. Log on to the ACK console.
2. On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Operations > Add-ons.
3. On the Logging and Monitoring tab, find and install ack-node-problem-detector.

Step 2: View the event center

Log on to the ACK console. In the left-side navigation pane, click Clusters.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Operations > Event Center.
Click Cluster Events Management in the upper-right corner. In the left-side navigation pane of the K8seventcenter page, click the icon to the left of your cluster to view information about Kubernetes events.
You can view all Kubernetes events and their detailed information and pod lifecycle. You can also send custom queries and configure alerts.

Scenario 2: Configure NPD to diagnose a cluster and send events of exceptions to sinks

NPD is a tool to diagnose Kubernetes nodes. NPD detects node exceptions, generates node events, and works with kube-eventer to raise alerts upon these events and enable closed-loop management of alerts. NPD generates node events when the following exceptions are detected: Docker engine hangs, Linux kernel hangs, outbound traffic exceptions, and file descriptor exceptions. Perform the following steps to install and configure NPD.

Refer to Install the ack-node-problem-detector component to install the ack-node-problem-detector component.
Note
If the ack-node-problem-detector component is already installed, reinstall it. For more information, see Reinstall the ack-node-problem-detector component.

Node diagnosis plug-ins supported by NPD are listed in the following table.

Plug-in	Feature	Description
fd_check	Checks whether the percentage of opened file descriptors on each cluster node exceeds a maximum of 80%	The default threshold is 80%. The threshold is adjustable. This plug-in consumes a considerable amount of resources to perform the check. We recommend that you do not enable this plug-in.
ram_role_check	Checks whether cluster nodes are assigned the required RAM role and whether the AccessKey ID and AccessKey secret are configured for the RAM role	None
ntp_check	Checks whether the system clocks of cluster nodes are properly synchronized through Network Time Protocol (NTP)	This plug-in is enabled by default.
nvidia_gpu_check	Checks whether the NVIDIA GPUs of cluster nodes can generate `Xid` messages	None
network_problem_check	Checks whether the `connection tracking (conntrack)` table usage on each cluster node exceeds 90%	This plug-in is enabled by default.
inodes_usage_check	Checks whether the `inode` usage on the system disk of each cluster node exceeds 80%	The default threshold is 80%. The threshold is adjustable. This plug-in is enabled by default.
csi_hang_check	Checks whether the Container Storage Interface (CSI) plug-in works as expected on cluster nodes	None
ps_hang_check	Checks whether processes in the uninterruptible sleep (D) state exist in the systems of cluster nodes	None
public_network_check	Checks whether cluster nodes can access the Internet	None
irqbalance_check	Checks whether the `irqbalance` daemon works as expected in the systems of cluster nodes	None
pid_pressure_check	Checks whether the ratio of `pid` processes in the node system to the maximum `pid` processes allowed in the kernel exceeds 85%	This plug-in is enabled by default.
docker_offline_check	Checks whether the `docker daemon` works as expected on cluster nodes	This plug-in is enabled by default.

On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Workloads > DaemonSets.
On the DaemonSets tab, select the kube-system namespace. You can find that ack-node-problem-detector-daemonset is running as expected.
When both NPD and eventer work as expected, the system sinks events and raises alerts based on the eventer configurations.

Scenario 3: Use DingTalk to raise alerts upon Kubernetes events

Using a DingTalk chatbot to monitor Kubernetes events and raise alerts is a typical scenario of ChatOps. To do this, perform the following steps.

Click in the upper-right corner of the chatbox of a DingTalk group to open the Group Settings page.
Click Bot and click Add Robot to add a chatbot. Custom is selected in this example.
On the Robot details page, click Add to open the Add Robot page.

Set the following parameters, read and accept the DingTalk Custom Robot Service Terms of Service, and then click Finished.

Parameter	Description
Edit profile picture	The avatar of the chatbot. This parameter is optional.
Chatbot name	The name of the chatbot.
Add to Group	The DingTalk group to which the chatbot is added.
Security settings	Three types of security settings are supported: custom keywords, additional signatures, and IP addresses (or CIDR blocks). Only Custom Keywords are supported for filtering alerts that are raised upon cluster events. Select Custom Keywords and enter `Warning` to receive alerts. If the chatbot frequently sends messages, you can add more keywords to filter the messages. You can add up to 10 keywords. Messages from ACK are also filtered through these keywords before the chatbot sends them to the DingTalk group.

Click Copy to copy the webhook URL.
Note
On the ChatBot page, find the chatbot and click to perform the following operations:
- Modify the avatar and name of the chatbot.
- Enable or disable message push.
- Reset the webhook URL.
- Remove the chatbot.
Refer to Install the ack-node-problem-detector component to install the ack-node-problem-detector component.
Note
If the ack-node-problem-detector component is already installed, reinstall it. For more information, see Reinstall the ack-node-problem-detector component.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side navigation pane, choose Applications > Helm.
On the Helm page, find the ack-node-problem-detector component. Then, click Update in the Actions column of the component, modify the following parameters, and click OK.
- In the npd section, set the enabled parameter to false.
- Set eventer.sinks.dingtalk.enabled to true.
- Enter the token that is contained in the webhook URL generated in Step 5.

Expected output:

eventer takes effect 30 seconds after the deployment is complete. When an event whose severity level exceeds the threshold occurs, an alert is sent to the DingTalk group. 消息提醒

Scenario 4: Sink Kubernetes events to Simple Log Service

You can sink Kubernetes events to Simple Log Service for persistent storage, and archive and audit these events. For more information, see Create and use an event center.

Create a Simple Log Service project and a Logstore.
1. Log on to the Simple Log Service console.
2. In the Projects section, click Create Project. In the Create Project panel, set the parameters and click OK.
  In this example, a Simple Log Service project named k8s-log4j is created in the China (Hangzhou) region where the monitored ACK cluster is deployed.
  Note
  We recommend that you create a Simple Log Service project in the same region as your cluster. When a Simple Log Service project and a cluster are deployed in the same region, the log is transmitted over the internal network. This enables the real-time collection and quick retrieval of log data. This also avoids cross-region transmission, which requires additional bandwidth and time costs.
3. In the Projects section, find and click the k8s-log4j project. The details page of the project appears.
4. On the Logstores tab, click the + icon to open the Create Logstore panel.
5. In the Create Logstore panel, set the parameters and click OK.
  In this example, a Logstore named k8s-logstore is created.
6. After the k8s-logstore Logstore is created, instructions on how to use the Data Import wizard appear on the page. Click Data Import Wizard. The Import Data dialog box appears.
7. Select Log4j 1/2 and configure the settings by following the steps on the page.
  In this example, the default settings are used. You can also customize the settings to meet your business requirements.
Configure log4j for the cluster.
1. Refer to Install the ack-node-problem-detector component to install the ack-node-problem-detector component.
Important
- When you install the ack-node-problem-detector component, specify the project and Logstore that you created in Step 1.
- If the ack-node-problem-detector component is already installed, reinstall it. For more information, see Reinstall the ack-node-problem-detector component.
1. On the Clusters page, find the cluster that you want to manage and click its name. In the left-side navigation pane, choose Applications > Helm.
2. On the Helm page, find the ack-node-problem-detector component. Then, click Update in the Actions column of the component, modify the following parameters, and click OK.
  - In the npd section, set the enabled parameter to false.
  - Set eventer.sinks.sls.enabled to true.
An event is generated after an operation is performed on the cluster, such as a pod deletion or an application creation. You can log on to the Simple Log Service console to view the collected log data. For more information, see Consume log data.
Set indexes and archiving. For more information, see Create indexes.
1. Log on to the Simple Log Service console. In the Projects section, find and click the name of the project.
2. Click next to the name of the Logstore and then select Search & Analysis.
3. In the upper-right corner of the page that appears, click Enable Index.
4. In the Search & Analysis panel, set the parameters.
5. Click OK.
  The log query and analysis page appears.
  Note
  The index configuration takes effect within 1 minute.
  A newly enabled or modified index applies only to data that is imported after the index is enabled or modified.
6. If you want to implement offline archiving and computing, you can ship data from the Logstore to Object Storage Service (OSS). For more information, see Ship log data to OSS.

Scenario 5: Sink Kubernetes events to EventBridge

EventBridge is a serverless event service provided by Alibaba Cloud. Alibaba Cloud services, custom applications, and software as a service (SaaS) applications can connect to EventBridge in a standardized and centralized manner. In addition, EventBridge can route events among these applications based on standardized CloudEvents 1.0 protocol. ACK events can be sunk to EventBridge, which allows you to build a loosely-coupled and distributed event-driven architecture in EventBridge. For more information about EventBridge, see What is EventBridge?.

Activate EventBridge. For more information, see Activate EventBridge and grant permissions to a RAM user.
Refer to Install the ack-node-problem-detector component to install the ack-node-problem-detector component.
Note
If the ack-node-problem-detector component is already installed, reinstall it. For more information, see Reinstall the ack-node-problem-detector component.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side navigation pane, choose Applications > Helm.
On the Helm page, find the ack-node-problem-detector component. Then, click Update in the Actions column of the component, modify the following parameters, and click OK.
Configure the Kubernetes event center and enable EventBridge as a sink of Kubernetes events.
- In the npd section, set the enabled parameter to true.
- In the eventer.sinks.eventbridge.enable section, set the parameter to true.
After EventBridge is enabled as a sink of Kubernetes events, you can view Kubernetes events in the EventBridge console.
1. Log on to the EventBridge console.
2. In the left-side navigation pane, click Event Buses.
3. On the Event Buses page, find the event that you want to view and click Event Tracking in the Actions column.
4. Select a query method, set query conditions, and then click Query.
5. In the list of events, find the event that you want to view and click Details in the Actions column.
In the Event Details dialog box, you can view the details of the event.

Reinstall the ack-node-problem-detector component

Log on to the ACK console. In the left-side navigation pane, click Clusters.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Workloads > Jobs.
On the Jobs page, click More on the right side of kube-eventer-init-v1.7-xxxx and click Delete.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Applications > Helm.
On the Helm page, delete the ack-node-problem-detector component.
On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Operations > Add-ons.
On the Logging and Monitoring tab, find and reinstall ack-node-problem-detector.