EP 105 - Service Unavailable - How To Code Well Podcast
Please consider supporting Anna Filina's Ukrainian relatives
Other ways to support the people of Ukraine
------
. In todays podcast we are going to talk about the 503 HTTP Status Code.
Error 503 = Service Unavailable
From the W3C:
The server is currently unable to handle the request due to a temporary overloading or maintenance of the server. The implication is that this is a temporary condition which will be alleviated after some delay. If known, the length of the delay MAY be indicated in a Retry-After header. If no Retry-After is given, the client SHOULD handle the response as it would for a 500 response.
Causes
- DDOS attacks will result in high resource usage which will eventually overload the server. As a result the server will respond with a 503 error code.
- A server might be temporarily un available if it is under going maintenance.
Its a server issue and not a client issue. So this wouldn’t be an issue with the HTML or CSS or client sided JavaScript
Trouble shooting
- Check any monitoring dashboards or graphs for resource hungry trends.
- Check the logs to find any server related errors.
- Check the logs for access requests to see if its a spike in traffic.
- Check if the server is going through an unexpected maintenance
- Check for firewall config. Perhaps a firewall on the network is preventing traffic from flowing.
- Check for long running scripts that could be causing memory leaks.
- Check for disk usage. Perhaps you are running out of swap space if that’s configured.
Solutions
- Stop any jobs that are running
- Divert traffic using a load balancer to another server
- Scale your application horizontally by bring on other servers/containers to handle the traffic
- Have an auto scaler which keeps adding or removing servers/containers when needed
- Reboot the server/container
Recommended Book
Getting Started in Tech: A guide to building a tech career by Amarachi Amaechi
Join our Discord server:
Coding Challenge:
Web development courses:
Listen to the podcast:
Related programming courses:
PHP Array Course
PHP OOP Course
JavaScript Array Course
️ Get my weekly newsletter
⏰ My current live coding schedule
Tuesdays 07:00
Sundays 14:30 All times are BST
️ Follow How To Code Well:
