<@ULVA73B9P> how to get notified when a worker nod...
# ask-marvin
l
@Marvin how to get notified when a worker node or scheduler node dies?
m
Oh, the joys of distributed systems. It's like trying to keep track of a bunch of toddlers in a candy store. When it comes to monitoring the health of worker or scheduler nodes, there are a few things you might want to consider: 1. Workers and agents should ideally complete any ongoing flow runs before terminating the process upon receiving a SIGTERM. This ensures that stopping an agent or worker executing flow runs is safe, provided they have enough time to finish their current tasks. 2. In environments like Kubernetes, where flow run execution happens outside the agent or worker, the worst-case scenario is that the flow crashes or becomes unresponsive. This is because the agent or worker is unavailable to detect the failure, leaving it in a running state. 3. To avoid interrupting scheduled flow runs for existing deployments, all deployments must be reassigned to a newly created work queue. Alternatively, it might be simpler to initiate a new agent or worker on the existing work queue and then decommission the old one. Here's a link to a discourse post that might be helpful. Remember, the key to managing distributed systems is constant vigilance and a healthy dose of pessimism. Good luck.
l
@Marvin I mean how to monitor cluster health metrics
m
Ah, the endless quest for stability in a universe of chaos. Monitoring cluster health metrics, you say? Well, there are a few ways to approach this, depending on how much you enjoy sifting through logs and metrics. 1. Logging: You can use logging services like Fluentd, Logstash, or Splunk to collect and analyze your cluster logs. These can give you insights into errors or issues that might affect your cluster's health. 2. Metrics: Tools like Prometheus can scrape metrics from your cluster and visualize them with Grafana. This can help you monitor things like CPU and memory usage, number of running pods, and other useful metrics. 3. Alerting: Once you have your logs and metrics set up, you can use alerting tools like Alertmanager or PagerDuty to notify you when certain conditions are met, such as high CPU usage or a large number of failed pods. 4. Kubernetes Events: Kubernetes events can provide valuable information about what's happening inside your cluster. You can use
kubectl events
to see these, or use a tool like EventRouter to ship them to a logging service. 5. Health Checks: Kubernetes supports liveness and readiness probes that can help you monitor the health of your applications. If a probe fails, Kubernetes can restart your application or stop sending traffic to it. 6. Managed Services: If all of this sounds like too much work, you can always use a managed Kubernetes service like Google Kubernetes Engine or Amazon EKS. These services provide their own monitoring tools that can make your life a bit easier. Remember, the universe is a chaotic place, and your cluster is no exception. Stay vigilant, stay informed, and maybe, just maybe, you'll achieve a semblance of stability. Good luck.