Re: RHEL7 kickstart: how is hostname determined?
"Lee, David (LA Int,RAL,LSCI)" <[email protected]> Tue, 8 Oct 2019 13:41:11 +0000
| Newsgroups | gmane.linux.redhat.kickstart.general |
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--===============8785293009318206329== Content-Language: en-GB Content-Type: multipart/alternative; boundary="_000_AM5PR01MB2929AFDEF385B8CD29ADD75CBE9A0AM5PR01MB2929eurp_" --_000_AM5PR01MB2929AFDEF385B8CD29ADD75CBE9A0AM5PR01MB2929eurp_ Content-Type: text/plain; charset="windows-1254" Content-Transfer-Encoding: quoted-printable Thanks, Gregory. I think we're getting there. But fixing the content of the returned DHCP/A= CK "domain-name" option doesn't fix the problem. Another subtle difference in the initial DHCP exchange is that for the good= network the returned DHCP 'ACK' includes a router (option 3), but on the s= mall subdomain, there is no router information in the ACK. For local reaso= ns, that subdomain is specifically un-routeable, and we use bastion hosts f= or access. So this configuration of not specifying a router is understanda= ble. If I adjust the Infoblox/DHCP entry for the host to specify a router addres= s (even though, of course, there is no router function at that address), th= en things work OK. So it seems that anaconda's(?) decision of whether or not to do that DNS PT= R query is based on the presence or absence of the router option from the p= receding DHCP/ACK. -- David ________________________________ From: [email protected] <[email protected]>= on behalf of Young, Gregory <[email protected]> Sent: 04 October 2019 15:01 To: Discussion list about Kickstart <[email protected]> Subject: RE: RHEL7 kickstart: how is hostname determined? I would start by fixing the DHCP on the subdomain subnet. You will want to = send the correct =93sub.company.org=94 for the option 15. Gregory Young From: [email protected] <[email protected]>= On Behalf Of Lee, David (LA Int,RAL,LSCI) Sent: October 4, 2019 4:22 AM To: [email protected] Subject: RHEL7 kickstart: how is hostname determined? All our hosts are registered in an Infoblox DHCP+DNS service as MAC+IP+host= name. We have two one domains and one subdomain. When we kickstart-install a new RHEL7 host on the main domain, it cleanly g= ets its intended hostname from Infoblox/DNS. We can see this very early on= by doing an Alt-F2 and querying the hostname. All is well. But on the subdomain it gets the name "localhost.localdomain" (which seems = to be the "in the absence of anything else" default). A wireshark trace of installations shows a DHCP request and ack. On the ma= in domain this is quickly followed by a DNS PTR query from the host, giving= the host's IP address and successfully returning the host's hostname. By = contrast, on the subdomain, this query is never initiated. (On both domain= s, there are subsequent successful DNS queries of other things as part of t= he ensuing installation, demonstrating that DNS activity is happening.) What might be triggering the hosts on the two different domains to behave d= ifferently, that is, send or not send that DNS/PTR query? Looking deeper into that preceding DHCP request/ACK: The main domain, wher= e all works well, is (for example) "company.org". The subdomain (where thi= s lack of hostname issue arises) is a subdomain, e.g. "sub.company.org". O= ne oddity I spotted, is that the DHCP/ACK returns the same "domain-name" op= tion-15 "company.org" for both. I wonder if that is precipitating a subseq= uent problematical behaviour in that "sub.company.org" context? Any thoughts? Thanks. -- David Lee -- This e-mail and any attachments may contain confidential, copyright and or = privileged material, and are for the use of the intended addressee only. If= you are not the intended addressee or an authorised recipient of the addre= ssee please notify us of receipt by returning the e-mail and do not use, co= py, retain, distribute or disclose the information in or attached to the e-= mail. Any opinions expressed within this e-mail are those of the individual and n= ot necessarily of Diamond Light Source Ltd. Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachme= nts are free from viruses and we cannot accept liability for any damage whi= ch you may sustain as a result of software viruses which may be transmitted= in or with the message. Diamond Light Source Limited (company no. 4375679). Registered in England a= nd Wales with its registered office at Diamond House, Harwell Science and I= nnovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom --_000_AM5PR01MB2929AFDEF385B8CD29ADD75CBE9A0AM5PR01MB2929eurp_ Content-Type: text/html; charset="windows-1254" Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dwindows-1= 254"> <style type=3D"text/css" style=3D"display:none;"> P {margin-top:0;margin-bo= ttom:0;} </style> </head> <body dir=3D"ltr"> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> Thanks, Gregory.</div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> <br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> I think we're getting there. But fixing the content of the returned D= HCP/ACK "domain-name" option doesn't fix the problem.<br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> <br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> Another subtle difference in the initial DHCP exchange is that for the good= network the returned DHCP 'ACK' includes a router (option 3), but on the s= mall subdomain, there is no router information in the ACK. For local = reasons, that subdomain is specifically un-routeable, and we use bastion hosts for access. So this configura= tion of not specifying a router is understandable.</div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> <br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> If I adjust the Infoblox/DHCP entry for the host to specify a router addres= s (even though, of course, there is no router function at that address), th= en things work OK.<br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> <br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> So it seems that anaconda's(?) decision of whether or not to do that DNS PT= R query is based on the presence or absence of the router option from the p= receding DHCP/ACK.</div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> <br> </div> <div style=3D"font-family: Calibri, Arial, Helvetica, sans-serif; font-size= : 12pt; color: rgb(0, 0, 0);"> -- David<br> </div> <div id=3D"appendonsend"></div> <hr style=3D"display:inline-block;width:98%" tabindex=3D"-1"> <div id=3D"divRplyFwdMsg" dir=3D"ltr"><font face=3D"Calibri, sans-serif" st= yle=3D"font-size:11pt" color=3D"#000000"><b>From:</b> kickstart-list-bounce= [email protected] <[email protected]> on behalf of Young, = Gregory <[email protected]><br> <b>Sent:</b> 04 October 2019 15:01<br> <b>To:</b> Discussion list about Kickstart <[email protected]>= ;<br> <b>Subject:</b> RE: RHEL7 kickstart: how is hostname determined?</font> <div> </div> </div> <style> <!-- @font-face {font-family:"Cambria Math"} @font-face {font-family:Calibri} p.x_MsoNormal, li.x_MsoNormal, div.x_MsoNormal {margin:0cm; margin-bottom:.0001pt; font-size:11.0pt; font-family:"Calibri",sans-serif} a:link, span.x_MsoHyperlink {color:#0563C1; text-decoration:underline} a:visited, span.x_MsoHyperlinkFollowed {color:#954F72; text-decoration:underline} p.x_msonormal0, li.x_msonormal0, div.x_msonormal0 {margin:0cm; margin-bottom:.0001pt; font-size:11.0pt; font-family:"Calibri",sans-serif} span.x_EmailStyle19 {color:black} .x_MsoChpDefault {font-size:10.0pt} @page WordSection1 {margin:72.0pt 72.0pt 72.0pt 72.0pt} div.x_WordSection1 {} --> </style> <div lang=3D"EN-CA" link=3D"#0563C1" vlink=3D"#954F72"> <div class=3D"x_WordSection1"> <p class=3D"x_MsoNormal"><span style=3D"color:black">I would start by fixin= g the DHCP on the subdomain subnet. You will want to send the correct =93su= b.company.org=94 for the option 15.</span></p> <p class=3D"x_MsoNormal"><span style=3D"color:black"> </span></p> <div> <p class=3D"x_MsoNormal"><b><span lang=3D"EN-US" style=3D"font-size:11.5pt;= color:#F99D1C"> </span></b></p> <p class=3D"x_MsoNormal"><b><span lang=3D"EN-US" style=3D"font-size:11.5pt;= color:#F99D1C">Gregory Young</span></b><span lang=3D"EN-US" style=3D"font-= size:11.5pt; color:#888888"></span></p> </div> <p class=3D"x_MsoNormal"><span style=3D"color:black"> </span></p> <div> <div style=3D"border:none; border-top:solid #E1E1E1 1.0pt; padding:3.0pt 0c= m 0cm 0cm"> <p class=3D"x_MsoNormal"><b><span lang=3D"EN-US">From:</span></b><span lang= =3D"EN-US"> [email protected] <kickstart-list-bounces@re= dhat.com> <b>On Behalf Of </b>Lee, David (LA Int,RAL,LSCI)<br> <b>Sent:</b> October 4, 2019 4:22 AM<br> <b>To:</b> [email protected]<br> <b>Subject:</b> RHEL7 kickstart: how is hostname determined?</span></p> </div> </div> <p class=3D"x_MsoNormal"> </p> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">All = our hosts are registered in an Infoblox DHCP+DNS service as MAC+IP&= #43;hostname. We have two one domains and one subdomain.</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">When= we kickstart-install a new RHEL7 host on the main domain, it cleanly gets = its intended hostname from Infoblox/DNS. We can see this very early o= n by doing an Alt-F2 and querying the hostname. All is well.</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">But = on the subdomain it gets the name "localhost.localdomain" (which = seems to be the "in the absence of anything else" default).</span= ></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">A wi= reshark trace of installations shows a DHCP request and ack. On the m= ain domain this is quickly followed by a DNS PTR query from the host, givin= g the host's IP address and successfully returning the host's hostname. By contrast, on the subdomain, this q= uery is never initiated. (On both domains, there are subsequent succe= ssful DNS queries of other things as part of the ensuing installation, demo= nstrating that DNS activity is happening.)</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">What= might be triggering the hosts on the two different domains to behave diffe= rently, that is, send or not send that DNS/PTR query?</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">Look= ing deeper into that preceding DHCP request/ACK: The main domain, whe= re all works well, is (for example) "company.org". The subd= omain (where this lack of hostname issue arises) is a subdomain, e.g. "sub.company.org". One oddity I spotted, is that the = DHCP/ACK returns the same "domain-name" option-15 "company.o= rg" for both. I wonder if that is precipitating a subsequent pro= blematical behaviour in that "sub.company.org" context?</span></p= > </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">Any = thoughts? Thanks.</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">&nbs= p;</span></p> </div> <div> <p class=3D"x_MsoNormal"><span style=3D"font-size:12.0pt; color:black">-- D= avid Lee</span></p> </div> <p> </p> <p>-- </p> <p>This e-mail and any attachments may contain confidential, copyright and = or privileged material, and are for the use of the intended addressee only.= If you are not the intended addressee or an authorised recipient of the ad= dressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclo= se the information in or attached to the e-mail.<br> Any opinions expressed within this e-mail are those of the individual and n= ot necessarily of Diamond Light Source Ltd. <br> Diamond Light Source Ltd. cannot guarantee that this e-mail or any attachme= nts are free from viruses and we cannot accept liability for any damage whi= ch you may sustain as a result of software viruses which may be transmitted= in or with the message.<br> Diamond Light Source Limited (company no. 4375679). Registered in England a= nd Wales with its registered office at Diamond House, Harwell Science and I= nnovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom<br> </p> </div> </div> </body> </html> --_000_AM5PR01MB2929AFDEF385B8CD29ADD75CBE9A0AM5PR01MB2929eurp_-- --===============8785293009318206329== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Kickstart-list mailing list [email protected] https://www.redhat.com/mailman/listinfo/kickstart-list --===============8785293009318206329==--