Hi Philippe, A deadlocked instance or an instance that is very slow in responding can cause this message. I have never tracked it down in the code, but I think it is just the wrong message (some code is catching a timeout exception and reporting it as this). It really means "Failed to get a response from an instance on ....". A deadlocked instance is the first thing that I check for when I see this.
For your deadlock: > java.lang.Thread.State: BLOCKED (on object monitor) > at > er.extensions.eof.ERXEnterpriseObjectCache.cache(ERXEnterpriseObjectCache.java:380) Do you have more than one EOF stack (Object Store Co-ordinator)? I have a deadlock to investigate related to that. Chuck On 2013-08-02, at 7:49 AM, Philippe Rabier wrote: > Hi All, > > I resurrect this discussion again ;-) > > We had today the same symptom "Failed to contact..." which was persistent. We > got this problem in the past but rarely. > > After googling "Failed to contact..." I found Kieran email. And we got the > same result when executing the following command: > ibabar:~ admin$ sudo lsof -i tcp | grep CLOSE_WAIT > java 34524 _appserver 137u IPv6 0x171e9344 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:58973 (CLOSE_WAIT) > java 34524 _appserver 138u IPv6 0x2148f5a8 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59191 (CLOSE_WAIT) > java 34524 _appserver 140u IPv6 0x2141d344 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59070 (CLOSE_WAIT) > java 34524 _appserver 144u IPv6 0x2e28c984 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59114 (CLOSE_WAIT) > java 34524 _appserver 145u IPv6 0x2db8bb2c 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59074 (CLOSE_WAIT) > java 34524 _appserver 146u IPv6 0x13509a70 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:58845 (CLOSE_WAIT) > java 34524 _appserver 152u IPv6 0x214440e0 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:58853 (CLOSE_WAIT) > java 34524 _appserver 158u IPv6 0x2db23400 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59155 (CLOSE_WAIT) > java 34524 _appserver 176u IPv6 0x2e23b19c 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59034 (CLOSE_WAIT) > java 34524 _appserver 178u IPv6 0x2102f8c8 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59163 (CLOSE_WAIT) > java 34524 _appserver 179u IPv6 0x21523d90 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59110 (CLOSE_WAIT) > java 34524 _appserver 184u IPv6 0x20c995a8 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59199 (CLOSE_WAIT) > java 34524 _appserver 187u IPv6 0x2e1f98c8 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59042 (CLOSE_WAIT) > java 34524 _appserver 190u IPv6 0x2df27664 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59046 (CLOSE_WAIT) > java 34524 _appserver 191u IPv6 0x2dd3b4bc 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59086 (CLOSE_WAIT) > java 34524 _appserver 193u IPv6 0x2e01cf38 0t0 TCP > ibabar.sophiacom.fr:dc->ibabar.sophiacom.fr:59050 (CLOSE_WAIT) > > After doing a dump, we saw the threads were locked as follow: > java.lang.Thread.State: BLOCKED (on object monitor) > at > er.extensions.eof.ERXEnterpriseObjectCache.cache(ERXEnterpriseObjectCache.java:380) > > My question is about the cause of the CLOSE_WAITs and JavaMonitor: why the > monitor is not able to contact the wotaskd because one instance is locked and > I presume because the wotask is not able to contact the instance above? > > I resurrect this mail because it's a good tip to use if someone get the > message "Failed to contact..." in the monitor. > > Cheers, > > Philippe > > On 30 avr. 2009, at 23:30, Kieran Kelleher wrote: > >> Resurrecting this old discussion again :-( >> >> OK, a while ago, one xserve "omega" (running Leopard Server 10.5.6, WO 5.4.X >> wotaskd with fully embedded WO 5.3.3 apps) showed up in WOMonitor as Failed >> to Contact again. Remember WOMonitor is running on Tiger Server 10.4.8 with >> the wotaskd from WO 5.3.3. >> >> Rather than assume this is a wotaskd/networking problem this time, I decided >> to check the WO apps on that server "192.168.3.154" using lsof and jstack to >> see if I can find anything unusual and I did: >> >> OK, 192.168.3.154 has 2 apps running on it. pid-479 port 2001) and pid-43 >> (port 2004). Also wotaskd is running as pid 43 >> >> app pid-479 lsof -i tcp:2001 shows nothing unusual >> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME >> java 479 _appserver 7u IPv6 0x830bb2c 0t0 TCP >> [::192.168.3.154]:dc (LISTEN) >> >> app pid-947 has unusual output, lsof -i tcp:2004 reveals 256 CLOSE_WAITs!!! >> .... this app is not allowing logins >> http://67.78.26.66:81/~kieran/misc/lsof_tcp_2004_pid_43.txt >> >> BTW, the other IP 192.168.3.149 shown on the CLOSE_WAIT lines is the machine >> that is running WOMonitor/apache, so this would seem to indicate a lot of >> hung requests? (that's a question, Chuck ;-) ) >> >> lsof for wotaskd itself gives this, which doesn't seem unusual >> bash-3.2# lsof -i tcp:1085 >> COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME >> java 43 _appserver 8u IPv6 0x6e1d258 0t0 TCP >> [::192.168.3.154]:webobjects (LISTEN) >> java 43 _appserver 11u IPv6 0x830b664 0t0 TCP >> [::192.168.3.154]:webobjects->[::192.168.3.154]:49665 (ESTABLISHED) >> java 43 _appserver 12u IPv6 0x8e41cd4 0t0 TCP >> [::192.168.3.154]:webobjects->[::192.168.3.154]:53449 (ESTABLISHED) >> java 479 _appserver 10u IPv6 0x830b8c8 0t0 TCP >> [::192.168.3.154]:49665->[::192.168.3.154]:webobjects (ESTABLISHED) >> java 947 _appserver 10u IPv6 0x8e7d344 0t0 TCP >> [::192.168.3.154]:53449->[::192.168.3.154]:webobjects (ESTABLISHED) >> >> >> Now looking at the jstack outputs, we also have more useful clues. >> >> jstack on the pid-947 (port 2004) app reveals it has session store >> deadlocks!! This is the same app with all the CLOSE_WAITs >> http://67.78.26.66:81/~kieran/misc/jstack_pid_947.txt >> >> So, it would seem that the stupid 'Failed to contact" stuff I have been >> seeing are really caused by Session Store deadlocks. So, the first thing I >> am going to do now is turn OFF concurrent request handling and turn on >> Wonder Session Store Deadlock detection for this app ...... however, I would >> wager that I will not see any Sesion Store deadlocks with concurrent request >> handling turned off! >> >> Any ideas on a strategy for deadlock detection with concurrent request >> handling ON? >> >> >> >> >> >> >> >> On Mar 25, 2009, at 10:34 PM, Chuck Hill wrote: >> >>> >>> On Mar 25, 2009, at 7:21 PM, Kieran Kelleher wrote: >>> >>>> Hi again Chuck, >>>> >>>> If you are going to use the the domain name (for example www.website.com, >>>> which resolves to 67.88.91.233 for example) doesn't that mean you have to >>>> open port 1085 on the router between public internet and that >>>> apache/WoMonitor machine? >>> >>> Apache is behind the firewall. Only ports 80 and 443 go though. >>> >>> >>> Chuck >>> >>> >>> >>>> -Kieran >>>> >>>> On Mar 23, 2009, at 12:25 PM, Chuck Hill wrote: >>>> >>>>> On Mar 21, 2009, at 6:35 PM, Kieran Kelleher wrote: >>>>> >>>>>> Hi Chuck, >>>>>> >>>>>> Still getting this problem after a few days of running .... last time we >>>>>> discussed, I had updated all the WO servers which run leopard to use IP >>>>>> address for host name...... I still have not touched the single only >>>>>> Tiger machine that is apache and runs the site's WOMonitor and has a >>>>>> couple tiny insignificant WO apps. I am not ready to upgrade this >>>>>> machine to a Leopard machine just yet, so I guess that is the next guy >>>>>> to be updated with IP addresses instead of its Bonjour name ..... but I >>>>>> have a question for you based on your experience with this: >>>>>> >>>>>> - For that primary WOMonitor machine which is the main site webserver, >>>>>> should I change to localhost, 127.0.0.1 or the actual IP address of the >>>>>> machine in WOMonitor Host settings and wotaskd properties? (FWIW, for >>>>>> last couple of years, we have used the Bonjour host.local name style on >>>>>> that machine) >>>>> >>>>> We usually use neither. We use the name that DNS lookups (reverse lookup >>>>> working is important too) to the primary IP on that machine. >>>> >>>> >>> >>> -- >>> Chuck Hill Senior Consultant / VP Development >>> >>> Practical WebObjects - for developers who want to increase their overall >>> knowledge of WebObjects or who are trying to solve specific problems. >>> http://www.global-village.net/products/practical_webobjects >>> >>> >>> >>> >>> >>> >> >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Webobjects-dev mailing list ([email protected]) >> Help/Unsubscribe/Update your Subscription: >> http://lists.apple.com/mailman/options/webobjects-dev/prabier%40mac.com >> >> This email sent to [email protected] > > > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Webobjects-dev mailing list ([email protected]) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/webobjects-dev/chill%40global-village.net > > This email sent to [email protected] -- Chuck Hill Executive Managing Partner, VP Development and Technical Services Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/gvc/practical_webobjects Global Village Consulting ranks 13th in 2012 in BIV's Top 100 Fastest Growing Companies in B.C! Global Village Consulting ranks 44th in 25th annual PROFIT 500 ranking of Canada’s Fastest-Growing Companies by PROFIT Magazine! _______________________________________________ Do not post admin requests to the list. They will be ignored. 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