Hey all,

We had a recent service outage and figured we should write a post-mortem of what happened and how we are going to prevent it from happening again.

On 2024-05-27 at 12:19 PM EST we became aware that our bouncer went offline. We quickly started investigating the cause and came up with a plan to get our services back online. Upon initial investigation our VM was unresposive and our immediate remediation was to force reboot it. This resolved the outage and got our services back online.

The following services were impacted:

• tuns
• bouncer
• feeds
• docker registry

Outage duration:

• Offline: 2024-05-27 at 11:02 AM EST
• Online: 2024-05-27 at 12:58 PM EST
• Total duration: 1 hour and 56 minutes

Once services were back online we started investigating the root cause. After looking at our resource monitoring and logs we discovered an underlying issue with tuns (our instance of sish).

Root Cause #

The root cause was our VM ran out of memory, here's the summary:

• We provide a tuns console so user's can view requests that are made to their tunnels (request inspection)
• That service requires request and response payloads to be loaded into memory
• Usage of tuns spiked yesterday and caused our VM to run out of memory
• VM became unresponsive

Prevention #

sish has a setting --service-console-max-content-length that let's us decide when to show the request/response payload to a user (reading it into memory). We are setting this to something within the confines of our VM's memory limits. We then stress tested this change to confirm it will prevent the root cause from happening again.

Monitoring #

We have an IRC channel (#pico.sh-ops) to receive alerts from our monitoring systems. We use prometheus for all of our services and we did receive alerts about the service outage. Unfortunately for us, we did not get pinged on our phones because we were no longer connected to IRC (through our bouncer).

We already have a bot that connects to our bouncer in order to send us emails for important messages, so we are going to extend this bot to send email alerts when it cannot connect successfully to our bouncer.

Conclusion #

We take service availability and uptime seriously and thank everyone for their patience.