Cases2 cases

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1. IL-0559 PubNub services degraded in US-East during an AWS outage in the IAD region, and failover load then degraded US-West

   PubNub2025

   Symptoms

   At 07:06 UTC on 20 October 2025, PubNub's monitoring alerted on raised error levels across multiple services in the IAD (US-East) region. Customers could see higher error rates and latency, and Presence was intermittently unavailable in IAD, SJC (US-West) and HND (AP-Northeast).

   High error rateHigh latency

   Trigger

   A broad infrastructure outage at AWS, PubNub's cloud provider, in the IAD (US-East) region.

   Root cause

   Cloud provider outage

   Component

   –

   Contributing factor

   No runbookCircular dependencyNo headroom

   Detection

   PubNub's monitoring systems alerted at 07:06 UTC on raised error levels across multiple services in IAD.

   Remediation

   • Started regional failover procedures and re-routed new connections to other regions
   • Reset established connections by hand
   • Re-routed Presence traffic to Frankfurt (EU-Central)
   • Brought on additional infrastructure in other regions to absorb traffic
   • Isolated the US-East region again when the second wave hit US-West
   • Scaled up balancer capacity in US-West
   • Rebalanced traffic after AWS restored service and US-East was confirmed stable

   Action items

   • Consolidate and centralise regional failover procedures so they are complete and immediately accessible for all production services
   • Fill gaps in process documentation for newer services before they are fully adopted into production
   • Fix internal tooling problems, including inventory and DNS resolution, that made mitigation harder

   View case
2. IL-0542 Twingate authentication and authorization requests failed at higher rates after traffic moved onto a smaller GKE cluster

   Twingate2025

   Symptoms

   On 21 March 2025, between 21:10 and 21:41 UTC, part of the authentication and authorization requests to Twingate services failed with elevated error rates.

   High error rate

   Trigger

   Twingate saw anomalies in one of its GKE clusters and scaled down the deployments in that cluster to protect the rest of the system, which moved its traffic to the other clusters.

   Root cause

   Cloud provider outage

   Component

   Cloud load balancerGKE control planeHorizontal pod autoscalerCluster autoscaler

   Contributing factor

   Retry stormNo headroomOverlapping failuresHarmful manual action

   Detection

   Twingate observed anomalies in one of its GKE clusters at the start of the incident.

   Remediation

   • Reintroduced capacity in the cluster that had been scaled down, so traffic was rebalanced across regions

   Action items

   • Keep working with the cloud provider to find the cause of the unexpected timeouts and of the cluster update's impact
   • Run deployments in all regions with the same number of replicas in the HPA configuration
   • Raise the maximum node counts of the cluster node autoscalers to leave more room to scale up
   • Configure the HPA to scale up faster

   View case

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