If you use Varnish Cache on your website or are visiting a website that caches content with Varnish Cache, chances are that at some point you will come across the server error Varnish Cache: Error 503 Service Unavailable / Guru Meditation with an XID number.
The Varnish Guru Meditation error 503 is a standard HTTP status code that indicates that the server encountered an internal problem that prevented it from fulfilling the request. This is usually a software malfunction, such as a memory error or an unexpected exception.
The error occurs when the Varnish cache fails to store a result. This can happen if there is not enough memory available in the system to cache this particular object. A 503 error can also occur if the object has been removed or if you are using invalid syntax in the request.
In some cases, this error code may also indicate a service outage or other planned or unplanned outage such as unscheduled maintenance.
When you see this error related to Varnish Cache, it means that the website is using Varnish Cache to cache and serve content and that Varnish Cache is unable to reach the backend server. Varnish Cache issues the Guru Meditation error when a connection has timed out or the Varnish Cache server made too many requests to the backend server without getting a response. Instead of making an infinite number of requests to an unhealthy backend, Varnish Cache issues the 503 error to allow the visitor (and website owner) it is likely that the website manager is already working on a fix and the best solution is to try again later. If you are the manager or owner of the website and are unsure why you are getting this response, read below to find out.
What to do if you get the Guru Meditation error?
If you are a regular visitor and have decided to google the error to understand what it means, you will now understand that the error is from the server and not from your browser. On your part, in short, there is nothing to be done from a technical point of view, if not try to call the owner of the site and make him aware of and participate in the error you see.
Much more likely there may be a maintenance operation in progress or a server-side issue resolution that will resolve itself within minutes or hours.
In short, if you do not have urgent urgency, try to come back later.
Fixed a Varnish Cache Server bug
If you are a system administrator and your website produces a Guru Meditation 503 error via Varnish Cache, how could you fix it? We first recommend that you review the logs for all 503 errors using varnishlog . You can have varnishlog log 503 errors using the following command from Varnish Cache :
$ varnishlog -q 'RespStatus == 503' -g request
Regularly you will get 503 errors because your backend is down or unhealthy. In this case, varnishlog might return something like "FetchError c no backend connection". You should check the port that Varnish Cache is trying to connect to, the origin server and your HTTP service like Apache or Nginx and see if everything is working fine - if not, you will have to troubleshoot your backend.
If your backend appears to be active but you are still getting a Varnish Cache 503 error, then there is something wrong with your web server connecting to Varnish Cache or Varnish Cache configuration.
If your backend responds but Varnish Cache is serving 503, we often find that this is due to timeout . You can change or add a .connect_timeout = Xs and a .first_byte_timeout = Xs in the default VCL section of the backend to a timeout duration that works for your web server. Varnish Cache Software has more information on the various timeouts that can occur in Varnish Cache . Another tip is to disable KeepAlive so that idle connections are dropped. This would look like this:
"origin": {
"address": "origin.example.com",
"disable_keepalive": true
}
For more information on Varnish Cache, contact us if you need help with troubleshooting Varnish Cache configuration.
