Difference between revisions of "User talk:Haoqili"
From K5Wiki
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(→Tips. Useful little things to know) |
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'''Python''' |
'''Python''' |
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*''p = Popen('blah', stdin=PIPE, stdout=PIPE, stderr=PIPE)'' |
*''p = Popen('blah', stdin=PIPE, stdout=PIPE, stderr=PIPE)'' |
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:''(out, err) = p.communicate('inputThing\n')'' <-- don't forget the return "\n" at the end! |
:''(out, err) = p.communicate('inputThing\n')'' <-- don't forget the return "\n" at the end! |
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:: exit |
:: exit |
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::</pre> |
::</pre> |
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* Two ways to display outputs after Popen( a command that has to get into something, in my case, getting into kadmin.local) 06262009 |
* Two ways to display outputs after Popen( a command that has to get into something, in my case, getting into kadmin.local) 06262009 |
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:Way 1: |
:Way 1: |
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::(out, err) = p.communicate('rest of command') #e.g. 'listprincs' |
::(out, err) = p.communicate('rest of command') #e.g. 'listprincs' |
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::print out |
::print out |
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| + | ::</pre> |
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| + | * Not type in a chunk of common code every time, i.e. |
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| + | :: ''p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)'' |
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| + | :This can be changed to: |
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| + | ::<pre> |
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| + | :: s = {stdin:PIPE, stdout=PIPE, stderr=PIPE} |
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| + | :: p = Popen(cmd, **s) |
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::</pre> |
::</pre> |
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Revision as of 15:04, 30 June 2009
Kerberos Bugs I've encountered and fixed (started loggin since Jun 24th).
- When trying to kinit username
- ERROR: kinit: Cannot contact any KDC for realm [your realm fqdn] while getting initial credentials
- SOLUTION: make sure KDC is running. /usr/local/sbin/krb5kdc
- SOLUTION: 1. check log file. I looked in /var/log/auth.log. The bottom of it says: Cannot create reply cache file /var/tmp/krb5kdc_rcache: File exits. 2. sudo rm /var/tmp/krb5kdc_rcache.
- Can't start krb5kdc and in auth.log it says:
- ERROR: Address already in use - Cannot bind server socket to port [#] address [IP address]
- SOLUTION: 1. see if it is true that port [#] is in use by netstat -nap | grep [#] (I also did pgrep -x krb5kdc). 2. kill the process: pkill -x krb5kdc. note the "-x" is for matching exactly the process "krb5kdc".
- When changing password 'kpasswd', Cannot contact any KDC for realm [your realm fqdn]
- and/or Can't start kadmind (know because echo $? = 1). The last chunk of auth.log says:
- ERROR:
- kadmind[6924]: No dictionary file specified, continuing without one.
- kadmind[6924]: setting up network...
- kadmind[6924]: Permission denied - Cannot bind server socket to port 464 address 0.0.0.0
- kadmind[6924]: setsockopt(6,IPV6_V6ONLY,1) worked
- kadmind[6924]: Permission denied - Cannot bind server socket to port 464 address ::
- kadmind[6924]: skipping unrecognized local address family 17
- kadmind[6924]: skipping unrecognized local address family 17
- kadmind[6924]: Permission denied - Cannot bind server socket to port 464 address 192.168.165.145
- kadmind[6924]: setsockopt(6,IPV6_V6ONLY,1) worked
- kadmind[6924]: Permission denied - Cannot bind TCP server socket on ::.464
- kadmind[6924]: Permission denied - Cannot bind RPC server socket on 0.0.0.0.749
- kadmind[6924]: set up 0 sockets
- kadmind[6924]: no sockets set up?
- Reason (provided by tlyu): It is trying to bind to a privileged port. you need to give it a different port number. actually, two different port numbers: one for password changing and one for normal kadmin.
- Solution:
- In kdc.conf inserted the last two lines here
- kdc_ports = 8888
- kpasswd_port = 8887
- kadmind_port = 8886
Python Bugs I've encountered and fixed
- When talking to the terminal shell, a command (in my case, kdbt_util add_mkey) asks for password twice (second time is confirmation). I first tried:
- p = Popen(command.split(), stdin=PIPE, stdout=PIPE, stderr=PIPE)
- (out, err) = p.communicate('password')
- (out2, err2) = p.communicate('password')
- When I ran it, I got a chunk of error that ends with: ValueError: I/O operation on closed file. So what happens is that communicate closes the pipe, it breaks (even if it only runs once).
- Solution code:
- p = Popen(command.split(), stdin=PIPE, stdout=PIPE, stderr=PIPE)
- p.stdin.write('password'+'\n')
- p.stdin.write('password'+'\n')
- Note don't forget the new line at the end.
Tips. Useful little things to know
Python
- p = Popen('blah', stdin=PIPE, stdout=PIPE, stderr=PIPE)
- (out, err) = p.communicate('inputThing\n') <-- don't forget the return "\n" at the end!
- When you're doing a bunch of p=Popen('shell command') be careful because Popen starts a new branch so the next Popen might start without the previous one having completed. To fix this problem, put in:
- if int(p.wait()) != 0: #meaning that it's not executed
- print "error message"
- exit
- Two ways to display outputs after Popen( a command that has to get into something, in my case, getting into kadmin.local) 06262009
- Way 1:
- p = Popen(['commannd', 'all', 'in', 'one', 'line'], stdin=PIPE, stdout=PIPE, stderr=PIPE) #e.g. ['kadmin.local', '-q', 'listprincs']
- if int(p.wait()) != 0:
- print p.stdout.readlines()
- Way 2:
- p = Popen(['command', 'front', 'chunk'], stdin=PIPE, stdout=PIPE, stderr=PIPE) #e.g. ['kadmin.local']
- (out, err) = p.communicate('rest of command') #e.g. 'listprincs'
- print out
- Not type in a chunk of common code every time, i.e.
- p = Popen(cmd, stdin=PIPE, stdout=PIPE, stderr=PIPE)
- This can be changed to:
- s = {stdin:PIPE, stdout=PIPE, stderr=PIPE}
- p = Popen(cmd, **s)
