The NOSRV can simply mean you have received a request that does not match your backend selection acls, common to bots probing for wordpress login page etc.
On Fri, 12 Oct 2018 12:23 am Michał Pasierb <[email protected]> wrote: > Hello, > > I did not mention it but all servers in c_backend have a httpchk > configured. There is nothing in the HAProxy logs indicating the servers or > the backend was not available during the time of the request. Indeed the > stats page shows only 4 health checks did not pass on each server since > HAProxy started and I know they were triggered by application deployment to > the servers. This is rock solid. The servers in the backend handle > thousands of requests during a day and log lines like these occur about 50 > times a day. > > I tried to replicate the termination state in my lab but I failed. I got > only CC--, CR-- and CD-- and http status is always set correctly (not to > -1). The origin log line has CH-- which indicates HAProxy was waiting for > reponse headers from a server so (this implies?) it connected somewhere. So > why server is marked as <NOSRV> ? > > Regards, > Michal > > On Thu, Oct 11, 2018 at 1:00 PM Aleksandar Lazic <[email protected]> > wrote: > >> Am 11.10.2018 um 10:33 schrieb Michał Pasierb: >> > Hello, >> > >> > I have a problem understanding a particular log line from HAProxy >> 1.7.11 in >> > production system. My clients report problems from time to time. They >> make >> > another request and all is OK. This is the log format used: >> > >> > log-format %tr\ %ci:%cp\ %ft\ %b/%s\ %TR/%Tw/%Tc/%Tr/%Ta\ %ST\ %B\ %CC\ >> %CS\ >> > %tsc\ %ac/%fc/%bc/%sc/%rc\ %sq/%bq\ %hr\ %hs\ %{+Q}r\ %ID\ %U\ >> %[res.comp] >> > >> > and the problematic log line: >> > >> > 02/Oct/2018:09:55:14.997 <ip-redacted>:46007 http-in c_backend/<NOSRV> >> > 44/-1/-1/-1/44 -1 25 - - CHNN 143/36/2/0/3 0/0 {} {} "PUT >> /api/xyz/status >> > HTTP/1.1" <id-redacted> 764 0 >> > >> > I can see that c_backend was properly selected based on acls. I can see >> that >> > client sent 764 bytes to HAProxy. The termination code is CH - client >> aborted >> > connection while HAProxy was waiting for headers from server. What >> server ? >> > There is <NOSRV> and connection time of -1. There were 3 connection >> retries. >> > HAProxy got 25 bytes from a server. The config contains: >> > >> > defaults >> > retries 3 >> > option redispatch >> > >> > Yet the retries is not +3 so it seems the redispatch did not take place. >> > >> > This is all confusing evidence. Can you explain what really happened ? >> >> None of the c_backend servers are reachable. >> I assume that the -1 value is the status_code. >> >> Cite from >> https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#8.2.3 >> >> ### >> >> - "status_code" is the HTTP status code returned to the client. This >> status >> is generally set by the server, but it might also be set by haproxy >> when >> the server cannot be reached or when its response is blocked by >> haproxy. >> >> ... >> >> - "server_name" is the name of the last server to which the connection >> was >> sent, which might differ from the first one if there were connection >> errors >> and a redispatch occurred. Note that this server belongs to the >> backend >> which processed the request. If the request was aborted before >> reaching a >> server, "<NOSRV>" is indicated instead of a server name. If the >> request was >> intercepted by the stats subsystem, "<STATS>" is indicated instead. >> ### >> >> I suggest to use some checks for the c_backend for example >> >> >> https://cbonte.github.io/haproxy-dconv/1.7/configuration.html#4-option%20httpchk >> >> > Thanks, >> > Michal >> >> Best regards >> Aleks >> >
