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From Jim Albert <...@netrition.com>
Subject Re: automatically restart httpd
Date Tue, 23 Apr 2013 19:39:14 GMT
On 4/23/2013 3:27 PM, Ryan Perry wrote:
>
>
>
> On Tue, Apr 23, 2013 at 2:09 PM, Jim Albert <jim@netrition.com
> <mailto:jim@netrition.com>> wrote:
>
>     On 4/23/2013 2:33 PM, Ryan Perry wrote:
>
>
>
>
>         On Tue, Apr 23, 2013 at 12:47 PM, Jim Albert <jim@netrition.com
>         <mailto:jim@netrition.com>
>         <mailto:jim@netrition.com <mailto:jim@netrition.com>>> wrote:
>
>              On 4/23/2013 1:36 PM, Ryan Perry wrote:
>
>
>
>
>                  On Tue, Apr 23, 2013 at 12:23 PM, Jim Albert
>         <jim@netrition.com <mailto:jim@netrition.com>
>                  <mailto:jim@netrition.com <mailto:jim@netrition.com>>
>                  <mailto:jim@netrition.com <mailto:jim@netrition.com>
>         <mailto:jim@netrition.com <mailto:jim@netrition.com>>>> wrote:
>
>                       On 4/23/2013 1:08 PM, Ryan Perry wrote:
>
>                           I've considered doing it daily via cron, but
>         if there's
>                  a way to
>                           do when
>                           I hit this error I'd prefer that.
>
>
>                           On Tue, Apr 23, 2013 at 12:02 PM, Jim Albert
>                  <jim@netrition.com <mailto:jim@netrition.com>
>         <mailto:jim@netrition.com <mailto:jim@netrition.com>>
>                           <mailto:jim@netrition.com
>         <mailto:jim@netrition.com> <mailto:jim@netrition.com
>         <mailto:jim@netrition.com>>>
>                           <mailto:jim@netrition.com
>         <mailto:jim@netrition.com> <mailto:jim@netrition.com
>         <mailto:jim@netrition.com>>
>                  <mailto:jim@netrition.com <mailto:jim@netrition.com>
>         <mailto:jim@netrition.com <mailto:jim@netrition.com>>>>>
wrote:
>
>                                On 4/23/2013 11:49 AM, Ryan Perry wrote:
>
>                                    I've been plagued by some bug that
>         makes a
>                  call to LWP
>                           stop working:
>                                    "Can't connect to 192.168.0.222 (Bad
>         hostname)"
>
>                                    I haven't been able to figure out
>         why, but a
>                  simple httpd
>                                    restart fixes
>                                    it for a day or 2.
>
>                                    Since I can't figure out a real fix, I'm
>                  wondering if
>                           there is a
>                                    way for
>                                    me to automatically restart httpd
>         whenever the bug
>                           hits.  Maybe
>                                    whenever
>                                    it appears in the httpd-error.log?
>           What are
>                  my options?
>
>
>                                Without more to go on to the actual cause
>         of the
>                  problem...
>
>                                Restarting apache daily isn't a bad idea in
>                  general if even
>                           just a
>                                graceful restart.
>                                kill -USR1 `cat /var/run/httpd.pid`
>                                which I believe should be safe any time
>         of day.
>
>                                If a complete restart, maybe early
>         morning off hours
>                           assuming your
>                                server requires a high degree of
>         availability?
>
>                                Jim
>
>
>                       Try to remember not to top-post, please. It makes
>         it hard
>                  for others
>                       to read the thread.
>
>                       I don't know, but it kind of has a DNS feel to it,
>                  possibly. Nothing
>                       concrete to go on, just past experience when I see
>         network
>                  and I
>                       know the network is fine... I think DNS. Maybe reverse
>                  resolution of
>                       your private IP address space assuming your
>         requests are
>                  being made
>                       to/from private addresses? That's really just a
>         shot in the
>                  dark
>                       because we don't have much to go on. I'd start
>         thinking
>                  network and
>                       DNS, put in some debug, see what if anything is
>         timing out.
>
>                       Jim
>
>
>                  Sorry about the top post.
>
>                  I've done the debugging on DNS.  If it try changing the
>                  IP/hostname I
>                  still get the error.  I think it's per-process though.
>           Once it
>                  starts
>                  to happen it's intermittent and gets worse, making me think
>                  depending
>                  which process I hit it will work or not until all
>         processes are
>                  affected.
>
>                  This is on FreeBSD using a jailed (virtualized) host.
>           I read about
>                  apache/jails on OpenBSD having a config issue with DNS
>         but it seemed
>                  different than this.
>
>                  It only seems to affect httpd, I can log in and ping
>         from the server
>                  just fine.
>
>
>              Also, please reply to the list, not personal email addresses so
>              everyone else gets the benefit of the thread, and maybe you
>         get a
>              better answer from someone other than me. :)
>
>              I'm not so sure you've eliminated DNS, yet.
>
>              What if from 192.168.0.222 you:
>              dig -x 192.168.0.x
>
>              where 192.168.0.x is the IP addressing making the connection to
>              192.168.0.222
>
>              Do you have reverse resolvers for your private address
>         space or are
>              the requests handled by the top level root servers?
>
>              Who is answering for that reverse resolution request?
>              dig -x 192.168.0.x
>              Is it your resolver or a root level like prisoner.iana.org
>         <http://prisoner.iana.org>
>              <http://prisoner.iana.org>
>
>
>              Jim
>
>
>         Interesting, but it seems hard to believe that would be it.  I don't
>         have any other suspects though...
>
>
>         ; <<>> DiG 9.8.3-P3 <<>> -x 192.168.0.200
>         ;; global options: +cmd
>         ;; Got answer:
>         ;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 20209
>         ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1,
>         ADDITIONAL: 0
>
>         ;; QUESTION SECTION:
>         ;200.0.168.192.in-addr.arpa.__INPTR
>
>         ;; AUTHORITY SECTION:
>         168.192.in-addr.arpa.__10800INSOAlocalhost. nobody.invalid. 1
>         3600 1200
>
>         604800 10800
>
>         ;; Query time: 6 msec
>         ;; SERVER: 4.2.2.1#53(4.2.2.1)
>         ;; WHEN: Tue Apr 23 18:28:37 2013
>         ;; MSG SIZE  rcvd: 103
>
>     You're using a public resolver... 4.2.2.1
>     I'm not saying that's your problem, but I've had problems in the
>     past where connections were slow or timed out doing a reverse lookup
>     of my private address space. The problem went away after configuring
>     my own resolvers to handle reverse lookups on my private address space.
>
>     If you want to continue to use 4.2.2.1 or any public resolver as
>     your resolver, that's not an option.
>
>     If you have your own resolvers, this might help:
>     http://www.sendmail.com/sm/__open_source/tips/private_dns/
>     <http://www.sendmail.com/sm/open_source/tips/private_dns/>
>
>     Again... I'm still kind of shooting in the dark, so my confidence
>     level on where I'm going with this is not high.
>
>     You really should put some debug in or maybe a packet trace... is
>     your server actually getting the request is where I would start.
>
>     Does your ISP provide a resolver? Is there a reason you want to use
>     4.2.2.1 rather than your ISP's or your own or maybe at least
>     Google's at 8.8.8.8?
>
>     Jim
>
>
> I do want to continue using it.  4.2.2.1 is L3's server.  8.8.8.8 is
> acutally my secondary.  If it were actually the DNS server it would
> affect more than just apache, right?
>
> I'd be interested in putting in some debug code, but I don't know where.
>   I'm just now reading about LWP::Debug.

That would depend on what processes attempt a reverse resolution. Some 
might do it simply for logging purposes. That was my problem before I 
set up reverse resolution of my private address space.

Again this is all supposition.

Jim



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