Hi Maryan,
I'm cc'ing the jmx-dev folks. (and bcc'ing the jdk7u-dev alias)
Hopefully they'll help move this conversation forward.
-Rob
On 27/01/14 20:42, Maryan Bagnyuk (aka Maryan Bahnyuk) wrote:
Hello
As a reporter of JI-9009639 / JDK-8031753
<https://bugs.openjdk.java.net/browse/JDK-8031753> bug I'd like to
inform you about the following.
Jaroslav Bachorík
<https://bugs.openjdk.java.net/secure/ViewProfile.jspa?name=jbachorik>added
a comment -2014-01-22 04:32
Not a regression.
Oops. Sorry. Indeed I should have left this field blank.
I'd understood the meaning of 'Regression' field incorrectly and had
filled it in bug report by mistake. :(
Jaroslav Bachorík
<https://bugs.openjdk.java.net/secure/ViewProfile.jspa?name=jbachorik>added
a comment -2014-01-22 04:32
If you insist on this issue being a regression, please, provide the
exact version where the behavior was as expected.
As I see all branches have this code for ages...
[marbug@server1 jdk]$ pwd && hg annotate -f -a -u -d -n -c
./src/share/classes/javax/management/remote/JMXServiceURL.java | grep
'local = InetAddress.getLocalHost();'
/home/marbug/cpp/jab/tmp/jdk6/jdk
ohair 9 2d585507a41b Fri Jan 30 16:27:33 2009 -0800
src/share/classes/javax/management/remote/JMXServiceURL.java: local =
InetAddress.getLocalHost();
[marbug@server1 jdk]$ pwd && hg annotate -r 0 -f -a -u -d -n -c
./src/share/classes/javax/management/remote/JMXServiceURL.java | grep
'local = InetAddress.getLocalHost();'
/home/marbug/cpp/jab/tmp/jdk6/jdk
duke 0 0c738a3e5791 Fri Jan 30 16:00:53 2009 -0800
src/share/classes/javax/management/remote/JMXServiceURL.java: local =
InetAddress.getLocalHost();
[marbug@server1 jdk]$ cd ../../jdk7u/jdk/
[marbug@server1 jdk]$ pwd && hg annotate -f -a -u -d -n -c
./src/share/classes/javax/management/remote/JMXServiceURL.java | grep
'local = InetAddress.getLocalHost();'
/home/marbug/cpp/jab/tmp/jdk7u/jdk
duke 0 37a05a11f281 Sat Dec 01 00:00:00 2007 +0000
src/share/classes/javax/management/remote/JMXServiceURL.java: local =
InetAddress.getLocalHost();
[marbug@server1 jdk]$ cd ../../jdk8/jdk/
[marbug@server1 jdk]$ pwd && hg annotate -f -a -u -d -n -c
./src/share/classes/javax/management/remote/JMXServiceURL.java | grep
'local = InetAddress.getLocalHost();'
/home/marbug/cpp/jab/tmp/jdk8/jdk
duke 0 37a05a11f281 Sat Dec 01 00:00:00 2007 +0000
src/share/classes/javax/management/remote/JMXServiceURL.java: local =
InetAddress.getLocalHost();
[marbug@server1 jdk]$ cd ../../jdk9/jdk/
[marbug@server1 jdk]$ pwd && hg annotate -f -a -u -d -n -c
./src/share/classes/javax/management/remote/JMXServiceURL.java | grep
'local = InetAddress.getLocalHost();'
/home/marbug/cpp/jab/tmp/jdk9/jdk
duke 0 37a05a11f281 Sat Dec 01 00:00:00 2007 +0000
src/share/classes/javax/management/remote/JMXServiceURL.java: local =
InetAddress.getLocalHost();
So the expected behaviour is just my conslusion/suggestion.
Jaroslav Bachorík
<https://bugs.openjdk.java.net/secure/ViewProfile.jspa?name=jbachorik>added
a comment -2014-01-22 04:32
I would argue that workaround should be L - it is easy to fix the
hostname and the solution is persistent. If the reporter can describe
a situation where fixing the hostname is not an option the workaround
should stay at M.
As I understand you suggest to fix hostname and/or an appropriate
record in /etc/hosts (under Linux).
Everyone suggest this in 'google search'... :( But IMHO it's not an
option because:
1) As far as I know no one must have root access to run programs with
JMX agent.
1.1) With this suggestion everyone must have root access (because only
root or sudo-ed user may change hostname and/or /etc/hosts)
1.1.1) What if someone do not have root access to his PC (some
companies do not allow to install additional software without their
permissions)?
1.1.2) Will you add the appropriate note to the 'Install' section in
Java manual/documentation? Or should everyone just google this
exception to find the fix of this issue? :)
2) Indeed Agent does not use hostname or it's IP to run JMX server
(please take a look at my original post)
2.1) If Agent does not use it (i.e. hostname/IP) then why should it
depend on it?
3) Why should I change hostname if other services work correctly
without it?
3.1) OS ignores that hostname can't be resolved to some IP and is
started successfully
3.2) Apache does so too (because it listens on 0.0.0.0 in IPv4)
3.3) SSH server as well ...
3.4) etc., etc., etc.
3.5) but java throws an exception
IMHO this does not follow the 'general' scheme ;)
4) How about JMX client (i.e. "Connecting to the JMX Agent
Programmatically ")?
http://docs.oracle.com/javase/7/docs/technotes/guides/management/agent.html#gdevg
STR:
4.1) server1 is behind NAT (example 1: on my VM, example 2: in Amazon
Cloud)
4.2) port mapping is configured from external IP to the local one
(i.e. there is only local network IP on interface)
4.3) I have associated my hostname (for instance,
server1.customer22.example.com) with 127.0.0.1 ( Is it a good idea to
do this in Amazon Cloud? IMHO no. ;) )
4.4) I start a program (Cassandra, Program4STR, etc.) via Agent
4.5) if someone will change a record for
server1.customer22.example.com to the correct external IP then why
should agent connect to external IP instead of local one? :)
4.5.1) if I run client on server1 then it's enough to connect to
localhost instead of external IP. Isn't it?
4.5.2) if I start client on another PC then in any case I'll pass the
needed value in 'host' parameter to JMXServiceURL(...)
5) etc., etc., etc. (see examples from my original post and imagine
how client will connect to JMX server in each case)
Indeed the decision is 'up to you' but IMHO making the suggested
change will simplify everything, save time of many people (they will
not need to change hostname and/or /etc/hosts), google will deprecate
search of ' Error: Exception thrown by the agent :
java.net.MalformedURLException: Local host name unknown:' string and
at least several developers and system administrators will be happy
not to take care about hostname ... At least for Java and programs
which use Agent ;)
Thanks
