Incident Library
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Cases62 cases

31 to 35 of 62

  1. IL-0151 A latent defect in the AWS Lambda Frontend, set off when one us-east-1 cell scaled past a size never reached before, raised errors for Lambda and for services that depend on it, including new EKS cluster provisioning
    Amazon Web Services2023
    Symptoms

    From 11:49 AM PDT on 13 June 2023, Lambda function invocations in the Northern Virginia (us-east-1) Region returned more errors and took longer. Customers that triggered functions from asynchronous or streaming event sources saw their event backlogs grow because the events were not being processed.

    High error rateHigh latencyCredentials unavailable
    Trigger

    At 11:49 AM PDT, while adding capacity for normal daily traffic growth, the Lambda Frontend fleet in one cell crossed a capacity threshold that no single cell had reached before.

    Root cause
    Software defect
    Component
    Serverless function platform
    Contributing factor
    Unknown limit
    Detection

    Engineering teams were engaged immediately and began investigating; by 12:26 PM PDT they had identified the latent defect and its effect on provisioning compute capacity.

    Remediation
    • scaled the Lambda Frontend fleet down to a size that no longer triggered the latent defect
    Action items
    • Disable the Lambda Frontend scaling activities that triggered the event
    • Fix the latent bug and deploy the fix to all Regions
    • Complete action items addressing the immediate concern with cellular scaling
    • Bound all cells to a well-tested size to avoid unexpected scaling issues
    Lessons

    A fleet that scales automatically can grow into a size that was never tested, and a defect that only appears at that size stays hidden until ordinary daily growth reaches it. AWS's answer is to cap every cell at a well-tested size. For EKS users, the event shows that provisioning new clusters in us-east-1 depended on Lambda, while clusters that were already running were not affected.

    View case
  2. IL-0060 Kubernetes 1.24 upgrade removed the master node label that Calico route reflectors selected on, dropping all pod routes and taking Reddit down for 314 minutes
    Reddit2023
    Symptoms

    About two minutes after an engineer started the Kubernetes 1.23 to 1.24 upgrade of the cluster running Reddit's legacy stack, just after 19:00 UTC, the site stopped. The CDN edge request graph, which is kept separate from the cluster, showed traffic by status collapsing. Users saw the error page, a homepage with no posts, or plain errors.

    Service outageHigh error rateDNS resolution failuresMonitoring outagePods stuck in ContainerCreatingControl plane lag
    Trigger

    An in-place upgrade of the legacy cluster from Kubernetes 1.23 to 1.24; in 1.24 the node-role.kubernetes.io/master label is removed even from running clusters.

    Root cause
    Breaking change in an upgrade
    Component
    CalicoKubernetes API serverAdmission webhooketcd
    Contributing factor
    Configuration not in codeUnrepresentative stagingUntested backupMonitoring blind spotSingle point of failure
    Detection

    The site broke about two minutes into the upgrade; an incident was opened immediately and responders were on the call within three minutes, working from CDN edge graphs because the cluster's own metrics were gone.

    Remediation
    • deleted the Open Policy Agent webhook configurations to stop API server timeouts
    • terminated all worker nodes of the cluster
    • restored the control plane from the pre-upgrade backup onto the first control plane node
    • switched off the cluster autoscaler until the control plane was stable
    • generated new TLS certificates so replacement control plane nodes could join etcd
    • brought traffic back in steps from 1% to 100%
    • restarted legacy services that had been stopped by hand
    Action items
    • Codify cluster configuration so every choice has a record, and document in detail what cannot be codified
    • Standardise components across clusters and replace bespoke configurations
    • Build tooling to manage the lifecycle of whole clusters so they can be recreated or replicated
    • Add pre-production clusters that can be tested with confidence
    • Improve the backup restore process and make cluster upgrades safe
    Lessons

    Configuration that exists only in a live cluster, edited by hand through a special tool, can be forgotten, as the route reflector setup was, and then break on an upgrade nobody connects it to. A Kubernetes upgrade cannot be reverted without a restore, so the restore procedure has to be kept current and practised. Consistent, codified clusters are what make upgrades testable; bespoke clusters keep producing outages.

    View case
  3. IL-0207 A routine task run from an engineer's local environment switched to production and deleted GitLab.com's Consul release, so Patroni lost Consul and GitLab.com returned 5xx errors to all traffic
    GitLab2022
    Symptoms

    GitLab's monitoring and alerting fired at once. One of the alerts reported a Patroni failover, and users of GitLab.com received 5XX errors; the CDN counted about 13 million requests answered with 503 during the outage.

    Service outageHigh error rateResources deleted
    Trigger

    An engineer ran a routine task with GitLab's tools in a local development environment; during a local deploy or rollback operation the tool's context changed from local development to production, and the change was applied to production.

    Root cause
    Operator error
    Component
    Database
    Contributing factor
    No safeguard on destructive change
    Detection

    GitLab's monitoring and alerting fired immediately; one of the alerts reported a Patroni failover.

    Remediation
    • re-applied the Consul release to the production Kubernetes cluster, with manual steps because the tooling did not support the redeploy directly
    Action items
    • Improve the Kubernetes deployment process to reduce the risk of running harmful deployment operations against production from local environments (https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/16875)
    • Integrate Teleport with the Kubernetes clusters, which could give SREs a read-only role by default (https://gitlab.com/gitlab-com/gl-infra/reliability/-/issues/16221)
    Lessons

    A tool that can switch its target from a local environment to production during a deploy or rollback turns routine local work into a production change. GitLab plans to improve its Kubernetes deployment process so that harmful deployment operations are less likely to be run against production from local environments, and to integrate Teleport with its clusters, which could give SREs a read-only role by default. Detection and diagnosis were fast because the alerts led straight from Patroni to its dependency, Consul. Bringing the deleted release back needed manual work, because the tooling did not make the redeploy straightforward, but it was still done relatively quickly.

    View case
  4. IL-0500 UToronto JupyterHub logins and server starts returned 500 errors when the hub's sqlite database disk filled up
    2i2c2022
    Symptoms

    On 31 October 2022 at 6:27 PM Pacific time, users of the UToronto JupyterHub run by 2i2c could no longer log in or start their servers, and the hub answered with 500 errors. Users who were already logged in could keep using the hub.

    High error ratePersistent volume full
    Trigger

    The JupyterHub log file, written to the same 10G disk as the hub's sqlite database, grew until the disk was completely full.

    Root cause
    Capacity exhaustion
    Component
    DatabasePersistent volumes and stateful setsJupyterHub
    Contributing factor
    No alert on limit
    Detection

    A user emailed 2i2c support at 7:13 PM that users could not log in; the team acknowledged the issue at 8:33 PM. There was no alert for the problem.

    Remediation
    • Compressed the hub log file into /tmp from a shell in the hub pod, because it could not be compressed in place on the full disk
    • Copied the compressed log to a local machine so the hub pod could be restarted without losing it
    • Resized the hub database disk (the hub-db-dir PVC) from 10G to 60G
    • Restarted the hub pod, which came back with the larger disk and restored service
    Action items
    • Stop keeping hub logs on the same disk as the hub database
    • Add a Grafana graph of free space on the JupyterHub database disk
    • Alert on elevated error rates
    Lessons

    Kubernetes dynamic volume resizing let the hub database disk grow from 10G to 60G without much effort. The risk of keeping logs on the database disk had been identified during the earlier migration, but the team had no solid process for following it through, and because no alert existed the team had to wait for a person to report the outage.

    View case
  5. IL-0178 On EKS, HPA scale-in returned 502 errors because containers stopped before their pod IPs left the Service endpoints, and after blue/green switches conntrack kept sending established connections to deleted pods behind an instance-mode ALB
    Lotte E-commerce2022
    Symptoms

    LOTTE ON, Lotte E-commerce's online shopping mall of about 40 microservices on Amazon EKS, returned errors for a period of time whenever the Horizontal Pod Autoscaler (HPA) scaled pods in after load dropped. Requests reached containers that had already been deleted and failed with 502 errors.

    High error rateIntermittent timeoutsStale endpoint routing
    Trigger

    HPA scale-in deleting pods, and the deletion of Blue pods after a blue/green switch of the Service label selector.

    Root cause
    DNS or network fault
    Component
    Horizontal pod autoscalerPod terminationkube-proxyconntrack tableCloud load balancerIngress controller
    Contributing factor
    Unreviewed defaults
    Remediation
    • delayed container shutdown on pod deletion (a wait in the SIGTERM handler or a preStop sleep, capped by terminationGracePeriodSeconds) so containers stop only after the pod has left the Service endpoints
    • switched some workloads' Ingress-created ALBs from instance mode to IP mode so traffic goes straight to pod IPs without iptables and conntrack
    Action items
    • Move all workloads to ALB IP mode gradually
    Lessons

    Removing a pod from Service endpoints and stopping its containers happen at the same time in Kubernetes, so a pod can stop while traffic is still routed to it unless shutdown is delayed with a preStop hook or in the application. With an instance-mode ALB, traffic passes through node iptables and conntrack, and established connections can keep going to a pod IP after its iptables rules are gone. IP mode avoids that path, within the limit of 1000 targets per target group.

    View case
Check your cluster for this

These 62 cases involve Database and Ingress controller. kubegap audits a Kubernetes cluster for gaps like these, read-only, from Claude Code or Codex; its checks cite public reports like the ones in this library.

Open kubegap

By root cause10

Configuration change14 cases

Component
Cloud load balancer2Client-side DNS resolver and cache2Helm2Kubernetes API server2Pod priority and preemption2Telemetry agent2Argo CD1cert-manager1Cilium1Configuration templating1ConfigMaps and Secrets1conntrack table1Container runtime1CoreDNS1Database1etcd1external-dns1HAProxy1HTTP and RPC client library1Ingress controller1kubelet1Linux kernel1Application logging library1Container memory limit1Persistent volumes and stateful sets1Prometheus1Terraform1AWS VPC CNI1
Contributing factor
Monitoring blind spot5Unverified assumption4Excessive blast radius4Automation amplification3Change with a delayed effect3Limited debug access2No configuration tests2No staged rollout2Retry storm2Missed in review2Unreviewed defaults1Cache-masked failure1Unknown limit1No alert on limit1No resource requests or limits1No runbook1No safeguard on destructive change1No headroom1Partial rollout1Unrepresentative staging1
Organisation
OpenAI3Datadog1DFDS1GitHub1GitLab1Grafana Labs1InfluxData1LIFULL1MUSINSA1NU.nl1Pusher1Wikimedia Foundation1
  1. IL-0179 With DEBUG logging and synchronous log output, a high-traffic service filled the 64 KB stdout pipe, so request threads blocked in write() while holding database connections and HikariCP ran dry, failing requests in 30-second bursts
    MUSINSA2026
  2. IL-0200 Newly provisioned Kubernetes nodes ran an incompatible etcd version and broke cluster consensus in several GitHub production clusters, causing 5XX errors on Git operations and page loads
    GitHub2026
  3. IL-0122 An invalid value in a configuration shared by several ChatGPT services put pods into crash loops and raised error rates
    OpenAI2025
  4. IL-0005 A new telemetry service overloaded the Kubernetes API servers of large clusters and broke DNS-based service discovery for all OpenAI services
    OpenAI2024
  5. IL-0118 A global change to Kubernetes namespace labels made the networking layer recompute metadata and overwhelmed the control planes of three of OpenAI's largest GPU clusters
    OpenAI2024
  6. IL-0459 MediaWiki on Kubernetes terminated TLS with a wrong certificate after a deployment, and 1% of requests failed
    Wikimedia Foundation2023
  7. IL-0009 A duplicated generated name made Argo CD replace the InfluxDB Cloud production Application and delete the whole production environment
    InfluxData2022
  8. IL-0461 Every rollout of Datadog's metrics query service on Kubernetes raised errors that the logs blamed on DNS
    Datadog2022
  9. IL-0208 A GitLab chart bump that renamed Kubernetes Service and Deployment ports made the GCP load balancer reconfigure, and GitLab.com slowed down and returned intermittent 50x errors
    GitLab2022
  10. IL-0442 Older pods on LIFULL's KEEL Kubernetes cluster were preempted all at once and the external error rate spiked
    LIFULL2021
  11. IL-0105 Replacing the AWS VPC CNI during a Terraform refactoring detached the ALB target groups, and every service in the Kubernetes cluster returned 503
    DFDS2021
  12. IL-0004 A new default pod priority let a new Cortex cluster preempt every production ingester in a cascade, taking Grafana Cloud Hosted Prometheus down
    Grafana Labs2019
  13. IL-0066 Broken ConfigMap change lay dormant for weeks, then took down Pusher's edge proxy when a cluster upgrade replaced its pods
    Pusher2019
  14. IL-0035 Worker nodes went NotReady after a new ElastAlert rule without memory limits used up node memory
    NU.nl2019

Capacity exhaustion21 cases

Component
Database6CoreDNS4Kubernetes API server4Node pool4Container memory limit3Pod scheduling and placement3Cloud block storage2In-memory cache2CI system2Client-side DNS resolver and cache2etcd2Helm2Jobs and CronJobs2Persistent volumes and stateful sets2Calico1conntrack table1Container CPU limit1Credential broker for pods1GKE control plane1HAProxy1Horizontal pod autoscaler1Model inference server1Ingress controller1JupyterHub1kube-proxy1kubelet1Linux kernel1Managed Kubernetes control plane and provider API1Pod termination1Container registry and its credentials1Service discovery1Telemetry agent1
Contributing factor
Unreviewed defaults5Single point of failure5Unverified assumption4Unknown limit4Monitoring blind spot4No alert on limit4Retry storm4Excessive blast radius3Unrepresentative staging3Automation amplification2Change during peak hours2Change with a delayed effect2Harmful manual action2No capacity planning2No headroom2No caching1No resource requests or limits1No runbook1No staged rollout1Ineffective rollback1
Organisation
Zalando32i2c1Civis Analytics1CyberAgent1freedesktop.org1GitHub1GitLab1Google Cloud1Honeycomb1IONOS Cloud1loveholidays1Microsoft1MonotaRO1Moonlight1PostHog1RebelMouse1Render1UC Berkeley1Wikimedia Foundation1
  1. IL-0471 GitHub Actions runs failed or sat queued for 9 hours after a routine deployment's pod replacement saturated capacity
    GitHub2026
  2. IL-0435 Error rates rose as Aurora MySQL killed connections and declined queries to avoid OOM while load metrics stayed flat
    CyberAgent2026
  3. IL-0465 IONOS Container Registry image pushes and pulls failed with 504 Gateway Timeout
    IONOS Cloud2026
  4. IL-0100 PostHog's feature flags pods were packed onto Kubernetes nodes that were too small for their CPU requests, and CPU saturation above 90% caused three outages in ten days through Redis overload, connection pool exhaustion and slow queries
    PostHog2025
  5. IL-0413 LLM inference engines timed out or ran out of resources under load in about 60% of 156 severe incidents at Microsoft
    Microsoft2025
  6. IL-0082 Losing one CoreDNS pod during a planned EKS node reroll overloaded the remaining CoreDNS pods, causing DNS timeouts and errors across multiple services at RebelMouse
    RebelMouse2025
  7. IL-0204 An etcd memory spike overloaded the control plane of a Render Frankfurt cluster, and DNS then failed because CoreDNS ran on the rebooted control plane nodes and could not start without the API server
    Render2024
  8. IL-0232 Calico pods in the codfw WikiKube cluster hit their resource limits and crash-looped, taking nodes out one by one
    Wikimedia Foundation2024
  9. IL-0202 A burst of queries and database writes exhausted connection pools and memory on Honeycomb's ingest hosts, and Kubernetes crash-loop back-off kept failed hosts offline so ingest capacity stayed too low to recover
    Honeycomb2023
  10. IL-0433 Shifting API traffic from EC2 to EKS on Fargate overloaded two CoreDNS pods and caused mass name-resolution errors
    MonotaRO2023
  11. IL-0500 UToronto JupyterHub logins and server starts returned 500 errors when the hub's sqlite database disk filled up
    2i2c2022
  12. IL-0140 The GKE API in us-central1 returned errors and high latency for 3 hours 19 minutes after an unexpected rise in backend traffic that client retries made worse
    Google Cloud2022
  13. IL-0206 Consul agents in GitLab.com's GKE pods were repeatedly OOM-killed, so the Rails pods lost database replica discovery and sent every query to the primary
    GitLab2022
  14. IL-0013 The conntrack table filled up on downsized GKE nodes and a high-traffic aggregation proxy saw climbing connection resets
    loveholidays2020
  15. IL-0002 CI builder pods could not get AWS IAM credentials because kubelet fell minutes behind its API rate limit
    Zalando2019
  16. IL-0064 CPU-heavy pods packed onto one Google Cloud node drove it to kernel panics, and the crash moved from node to node until the site was down
    Moonlight2019
  17. IL-0075 Kubernetes API servers pegged on CPU when the cluster grew to about 290 nodes, traced to Datadog agents polling the API
    Civis Analytics2019
  18. IL-0001 Cluster-wide DNS outage after CoreDNS pods were OOM-killed again and again under a burst of DNS queries
    Zalando2019
  19. IL-0031 Kubernetes API server OOM-killed, leaving the Skipper ingress without routes; the talk points to a misconfigured CronJob manifest
    Zalando2018
  20. IL-0518 gitlab.freedesktop.org on GKE ran short of volume space and a planned 30-minute storage upgrade became a 4-hour outage
    freedesktop.org2018
  21. IL-0468 New JupyterHub student pods stuck Pending on MaxVolumeCount after a memory limit cut with node size unchanged
    UC Berkeley2017

Cloud provider outage5 cases

Component
Database3Cloud load balancer2AKS control plane1CDN and edge network1Cluster autoscaler1GKE control plane1Horizontal pod autoscaler1Ingress controller1Node root disk1Persistent volumes and stateful sets1Web application firewall rules1
Contributing factor
Overlapping failures2Single point of failure2Unverified assumption1Excessive blast radius1Unpatched known bug1Harmful manual action1No headroom1Health check tied to a dependency1Retry storm1
Organisation
ANDPAD1Grafana Labs1Microsoft Azure1OpenAI1Twingate1
  1. IL-0438 Builder Work became almost entirely unreachable with 504 errors when the Amazon CloudFront VPC Origins feature failed
    ANDPAD2026
  2. IL-0542 Twingate authentication and authorization requests failed at higher rates after traffic moved onto a smaller GKE cluster
    Twingate2025
  3. IL-0119 ChatGPT web service pods crash-looped on failing health checks after a Cosmos DB failure, leaving too few healthy pods to serve the web layer
    OpenAI2025
  4. IL-0145 A power sag and chiller failure in one Australia East availability zone took down the AKS control plane's compute and its non-zone-redundant SQL Database operation queue, blocking AKS create, update and delete operations in Australia East and Australia Southeast
    Microsoft Azure2023
  5. IL-0193 A GCP persistent disk degradation took down a Cassandra StatefulSet whose OrderedReady policy blocked recovery, and Metrictank could not reconnect to the recreated pods, causing a 23-hour Graphite query outage
    Grafana Labs2019

Breaking change in an upgrade4 cases

Component
Admission webhook1Calico1etcd1Model inference server1Ingress controller1Istio1Kubernetes API server1Linux kernel1Web application firewall rules1
Contributing factor
Unrepresentative staging2Untested backup1Configuration not in code1Ignored early signal1Monitoring blind spot1Single point of failure1
Organisation
GitHub1Reddit1UK Ministry of Justice1Wikimedia Foundation1
  1. IL-0092 Upgrading ingress-nginx from 1.12.0 to 1.14.3 brought a newer ModSecurity and OWASP Core Rule Set whose false positives blocked HMPPS Auth, so users could not sign in to their applications
    UK Ministry of Justice2026
  2. IL-0236 After an Istio 1.15 to 1.24 upgrade, half of Wikimedia's ML model servers returned 5XX for about a day
    Wikimedia Foundation2026
  3. IL-0201 A framework upgrade caused kernel panics in GitHub's Kubernetes infrastructure, and GitHub.com web and API requests, mostly for issues and pull requests, failed intermittently for about 16 hours
    GitHub2025
  4. IL-0060 Kubernetes 1.24 upgrade removed the master node label that Calico route reflectors selected on, dropping all pod routes and taking Reddit down for 314 minutes
    Reddit2023

Faulty deployment2 cases

Component
In-memory cache1CI system1Cloud load balancer1ConfigMaps and Secrets1Database1Helm1Ingress controller1Pod termination1
Contributing factor
Unverified assumption2Signal buried in noise1Unreviewed defaults1Monitoring blind spot1Dependence on a warm cache1
Organisation
Wikimedia Foundation1Yonghyun Kim1
  1. IL-0188 Rolling updates on EKS returned 502 errors for about 30 seconds because Kubernetes deleted old pods as soon as new pods passed readiness, before the ALB had marked the new pod targets healthy
    Yonghyun Kim2025
  2. IL-0324 Three MediaWiki deployments lost Memcached after a PHP 8.1 rollout and overloaded the External Storage database cluster
    Wikimedia Foundation2025

Data loss or corruption1 case

Component
Container registry and its credentials
Contributing factor
Cache-masked failure
Organisation
Harness
  1. IL-0474 Harness Feature Flags auth returned 502s when rescheduled pods could not get an image deleted from Artifact Registry
    Harness2025

Software defect9 cases

Component
kubelet3Cloud load balancer2etcd2Ingress controller2Admission webhook1Container CPU limit1Database1Authoritative DNS servers and records1Liveness and readiness probes1Horizontal pod autoscaler1Kubernetes API server1Linkerd1Linux kernel1Node pool1Serverless function platform1
Contributing factor
Monitoring blind spot3Automation amplification2Change with a delayed effect2Unpatched known bug2Unknown limit2Excessive blast radius1Unreviewed defaults1Ignored early signal1Harmful manual action1No configuration tests1No runbook1No safeguard on destructive change1No headroom1Overlapping failures1Retry storm1Ineffective rollback1Single point of failure1
Organisation
Amazon Web Services2Airbnb1AirMap1DFDS1Grafana Labs1HubSpot1Monzo1Omio1
  1. IL-0150 A latent race condition in DynamoDB's DNS automation left an empty DNS record for dynamodb.us-east-1.amazonaws.com, and the DynamoDB and EC2 launch failures that followed caused EKS, ECS and Fargate container launch failures and cluster scaling delays in us-east-1
    Amazon Web Services2025
  2. IL-0495 HubSpot's internal load balancers on Kubernetes were falsely marked unhealthy and the rest collapsed under the traffic
    HubSpot2024
  3. IL-0151 A latent defect in the AWS Lambda Frontend, set off when one us-east-1 cell scaled past a size never reached before, raised errors for Lambda and for services that depend on it, including new EKS cluster provisioning
    Amazon Web Services2023
  4. IL-0106 A malformed Traefik IngressRoute triggered a Traefik v2 bug once a node rollover restarted every Traefik pod, and all Kubernetes services returned 404
    DFDS2021
  5. IL-0032 Mutating admission controller generated broken JSON patches, silently blocking deploys for a week until a production service ran down to two pods
    Airbnb2020
  6. IL-0190 Cortex distributors kept a stuck connection to a dead etcd leader after a Kubernetes upgrade terminated its node, failing writes to Hosted Prometheus for 12 minutes
    Grafana Labs2020
  7. IL-0012 CPU limits and an unpatched kernel CFS quota bug throttled multi-threaded services into stalls, failed health checks and timeouts
    Omio2020
  8. IL-0074 All AirMap platform services down as worker nodes went NotReady and pods crash-looped on network and DNS failures
    AirMap2018
  9. IL-0003 linkerd lost Kubernetes service discovery after an etcd reconfiguration, and restarting every linkerd instance turned failed payments into a full platform outage
    Monzo2017

Certificate or credential expiry1 case

Component
Cluster autoscalerManaged Kubernetes control plane and provider API
Contributing factor
Change with a delayed effect
Organisation
Linode
  1. IL-0156 Revoking old certificates after a rotation left a certificate key mismatch between API endpoints and the cluster controller, and LKE cluster management and autoscaling in Atlanta returned 5xx errors
    Linode2025

DNS or network fault3 cases

Component
conntrack table2CoreDNS2kube-proxy2Cloud load balancer1Client-side DNS resolver and cache1Horizontal pod autoscaler1Ingress controller1Pod termination1Telemetry agent1
Contributing factor
Unreviewed defaults2Ignored early signal2Unverified assumption1Automation amplification1Unknown limit1No caching1
Organisation
Adevinta1Lotte E-commerce1Preply1
  1. IL-0083 Intermittent 5xx errors in a multi-tenant Kubernetes cluster came from internal DNS: the node-local dnsmasq hit its 150 concurrent query limit, did not cache cluster.local answers, and ndots search lookups flooded CoreDNS
    Adevinta2023
  2. IL-0178 On EKS, HPA scale-in returned 502 errors because containers stopped before their pod IPs left the Service endpoints, and after blue/green switches conntrack kept sending established connections to deleted pods behind an instance-mode ALB
    Lotte E-commerce2022
  3. IL-0049 Partial DNS outage after CoreDNS scaled down and kube-proxy failed to delete stale conntrack entries
    Preply2020

Operator error2 cases

Component
Database1Ingress controller1Model hub1
Contributing factor
No safeguard on destructive change2No headroom1Overlapping failures1Deferred upgrades1
Organisation
GitLab1OpenAI1
  1. IL-0207 A routine task run from an engineer's local environment switched to production and deleted GitLab.com's Consul release, so Patroni lost Consul and GitLab.com returned 5xx errors to all traffic
    GitLab2022
  2. IL-0115 One of OpenAI's three production AKS clusters went offline through a human error, and rebuilding it took 10½ hours because an AKS Kubernetes upgrade broke the ingress and AKS cannot be downgraded
    OpenAI2022