In an earlier post I discussed in general terms deploying SSSD on CentOS 7 which is fairly straightforward once the right choices have been made.
I have now successfully deployed it on CentOS 6. This blog post by one of the authors of SSSD gave me the initial clues. The key point is that while sssd and associated packages are available on CentOS 6, realmd is not so you have to do those steps manually using adcli.
There was one big problem though, the join command didn't work for me! When it came to that step I got an error message saying I had insufficient permissions to modify the computer entry in AD. I tried various permutations but still got the same error.
Finally I decided to examine the progress messages of realm -v join on a CentOS 7 machine to see what it was doing under the hood. It turned out to be a command of this form:
net -s /tmp/sssd-smb.tmpfile ads join example.com
So it was using the Samba net command, not adcli for joining!
The temporary file providing the settings to net was of the form:
[global]
workgroup = EXAMPLE
netbios name = MYWORKSTATION-N
realm = EXAMPLE.COM
kerberos method = system keytab
security = ads
Note that the netbios name should be truncated to 15 characters. The reason net is used is explained in the last comment of this bug report.
Now I don't know if realm switched to calling net when it detected that adcli would not work, or uses net since that blog post was written, to satisfy servers that don't allow creation/modification of computer entries with LDAP. I think the latter because realmd comes from the CentOS repo while adcli comes from EPEL repo so can't be a dependency. I suppose I could look at the code.
The next command that realm runs is:
net -s /tmp/sssd-smb.tmpfile ads keytab create
Once that is done, you will be able to run klist -k and get output. Then follow the rest of the blog post to set up sssd. If you were running /etc/passwd authentication, remember to delete those entries in passwd, group, shadow, and gshadow so that they don't mask the user entries from AD. Restart nscd to flush any cached entries afterwards. In the long term you want to follow RedHat's recommendations referred to in my CentOS 7 blog post to disable nscd caching for user and group entries.
I have now successfully deployed it on CentOS 6. This blog post by one of the authors of SSSD gave me the initial clues. The key point is that while sssd and associated packages are available on CentOS 6, realmd is not so you have to do those steps manually using adcli.
There was one big problem though, the join command didn't work for me! When it came to that step I got an error message saying I had insufficient permissions to modify the computer entry in AD. I tried various permutations but still got the same error.
Finally I decided to examine the progress messages of realm -v join on a CentOS 7 machine to see what it was doing under the hood. It turned out to be a command of this form:
net -s /tmp/sssd-smb.tmpfile ads join example.com
So it was using the Samba net command, not adcli for joining!
The temporary file providing the settings to net was of the form:
[global]
workgroup = EXAMPLE
netbios name = MYWORKSTATION-N
realm = EXAMPLE.COM
kerberos method = system keytab
security = ads
Note that the netbios name should be truncated to 15 characters. The reason net is used is explained in the last comment of this bug report.
Now I don't know if realm switched to calling net when it detected that adcli would not work, or uses net since that blog post was written, to satisfy servers that don't allow creation/modification of computer entries with LDAP. I think the latter because realmd comes from the CentOS repo while adcli comes from EPEL repo so can't be a dependency. I suppose I could look at the code.
The next command that realm runs is:
net -s /tmp/sssd-smb.tmpfile ads keytab create
Once that is done, you will be able to run klist -k and get output. Then follow the rest of the blog post to set up sssd. If you were running /etc/passwd authentication, remember to delete those entries in passwd, group, shadow, and gshadow so that they don't mask the user entries from AD. Restart nscd to flush any cached entries afterwards. In the long term you want to follow RedHat's recommendations referred to in my CentOS 7 blog post to disable nscd caching for user and group entries.
