Bug 619289
| Summary: | virt-v2v stuck on remote connection when the remote host only has rDNS | ||||||
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| Product: | Red Hat Enterprise Linux 6 | Reporter: | Rita Wu <rwu> | ||||
| Component: | virt-v2v | Assignee: | Matthew Booth <mbooth> | ||||
| Status: | CLOSED WONTFIX | QA Contact: | Virtualization Bugs <virt-bugs> | ||||
| Severity: | medium | Docs Contact: | |||||
| Priority: | medium | ||||||
| Version: | 6.0 | CC: | cwei, moli, mshao | ||||
| Target Milestone: | rc | Keywords: | RHELNAK | ||||
| Target Release: | --- | ||||||
| Hardware: | All | ||||||
| OS: | Linux | ||||||
| Whiteboard: | |||||||
| Fixed In Version: | Doc Type: | Bug Fix | |||||
| Doc Text: | Story Points: | --- | |||||
| Clone Of: | |||||||
| : | 619300 (view as bug list) | Environment: | |||||
| Last Closed: | 2010-07-29 10:36:34 UTC | Type: | --- | ||||
| Regression: | --- | Mount Type: | --- | ||||
| Documentation: | --- | CRM: | |||||
| Verified Versions: | Category: | --- | |||||
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |||||
| Cloudforms Team: | --- | Target Upstream Version: | |||||
| Embargoed: | |||||||
| Bug Depends On: | |||||||
| Bug Blocks: | 619300 | ||||||
| Attachments: |
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This issue has been proposed when we are only considering blocker issues in the current Red Hat Enterprise Linux release. ** If you would still like this issue considered for the current release, ask your support representative to file as a blocker on your behalf. Otherwise ask that it be considered for the next Red Hat Enterprise Linux release. ** I can't think of anything that virt-v2v does which might cause this. I strongly suspect it's just an SSH configuration quirk. The first thing I'd try is disabling GSSAPI for the connection. Can you please add the following lines to ~/.ssh/config (create the file if necessary): Host 10.66.93.194 GSSAPIAuthentication no and re-run the test. (In reply to comment #3) > I can't think of anything that virt-v2v does which might cause this. I strongly > suspect it's just an SSH configuration quirk. > > The first thing I'd try is disabling GSSAPI for the connection. Can you please > add the following lines to ~/.ssh/config (create the file if necessary): > > Host 10.66.93.194 > GSSAPIAuthentication no > > and re-run the test. After configuring ~/.ssh/config, v2v can convert a guest from remote machine successfully. In that case, what about popping up message about the problem/soution, otherwise users are waiting without any hints. Unfortunately there's no way we can reasonably detect this before it happens, which means we have no opportunity to display a warning to the user. Even if the connection does hang, there are so many potential reasons for it we couldn't reasonably diagnose it without writing a massive general purpose SSH diagnosis library. We can't even just check for GSSAPIAuthentication being disabled because many organisations (Red Hat, for example) use it. Misconfigured DNS can cause all sorts of problems. This one is an issue with SSH, so I'm going to close it. i think it's better to added this to the document, when user met such problem, it will be much helpful, as when we met this problem, it also cause us some time to debug. two points could be added to the document when remote connection get no any response(no data transfer after a long time), 1, check the DNS setting, check the reverse/positive dns resolve 2, check the SSH setting, ~/.ssh/config (create the file if necessary): Host 10.66.93.194 GSSAPIAuthentication no This is just a generic SSH issue. If we start documenting things like this explicitly for virt-v2v, we risk making the documentation unreadable due to misconfiguration warnings. We certainly can't just recommend disabling GSSAPI. I'd leave it out. |
Created attachment 435205 [details] strace.log Description of problem: While running virt-v2v with xen+ssh remote connection, it just stuck there and didn't do anything. [root@dhcp-66-92-183 ~]# virsh -c xen+ssh://10.66.93.194 list --all Id Name State ---------------------------------- 0 Domain-0 running - 2008_6 shut off - 2008R2-3 shut off - win2003 shut off - win2003_1 shut off - win2008R2 shut off - win2k3_64 shut off - win2k3_64_1 shut off - xen-rhel54-64-pv-raw.img shut off (have configured ssh keys authentication ) [root@dhcp-66-92-183 ~]# virt-v2v -ic xen+ssh://10.66.93.194 -o rhev -osd 10.66.90.115:/vol/v2vrwu/rwuv2v xen-rhel54-64-pv-raw.img <hange here, nothing displayed, conversion didn't begin> here is part of the strace log, please refer to the attachment for detail. ------------------------------------ [...] lseek(13, 0, SEEK_CUR) = -1 ESPIPE (Illegal seek) fcntl(12, F_SETFD, FD_CLOEXEC) = 0 fcntl(13, F_SETFD, FD_CLOEXEC) = 0 clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x7ff9e2dbc9d0) = 17412 close(7) = 0 close(11) = 0 close(13) = 0 select(16, [10 12], NULL, NULL, NULL) = 1 (in [12]) read(12, "reverse mapping checking getaddr"..., 4096) = 120 read(12, ------------------------------------ virt-v2v stuck on "read(12,", and there is some error message which should comes from ssh connection "reverse mapping checking getaddr"... [root@dhcp-66-92-183 ~]# ps aux | grep virt-v2v root 17406 0.6 0.0 4308 788 pts/5 S+ 12:53 0:00 strace -o /tmp/ssh.log virt-v2v -ic xen+ssh://10.66.93.194 -o rhev -osd 10.66.90.115:/vol/v2vrwu/rwuv2v xen-rhel54-64-pv-raw.img root 17407 1.9 0.4 279656 28036 pts/5 S+ 12:53 0:00 /usr/bin/perl /usr/bin/virt-v2v -ic xen+ssh://10.66.93.194 -o rhev -osd 10.66.90.115:/vol/v2vrwu/rwuv2v xen-rhel54-64-pv-raw.img root 17437 0.0 0.0 103148 828 pts/4 S+ 12:53 0:00 grep virt-v2v [root@dhcp-66-92-183 ~]# ll /proc/17407/fd/12 lr-x------. 1 root root 64 Jul 29 12:54 /proc/17407/fd/12 -> pipe:[141736] [root@dhcp-66-92-183 ~]# lsof | grep 141736 virt-v2v 17407 root 12r FIFO 0,8 0t0 141736 pipe ssh 17412 root 2w FIFO 0,8 0t0 141736 pipe ssh 17412 root 10w FIFO 0,8 0t0 141736 pipe Our dns configuration only have the dns reverse name resolution for this host: [root@dhcp-66-92-183 ~]# host 10.66.93.194 194.93.66.10.in-addr.arpa domain name pointer dhcp-93-194.nay.redhat.com. [root@dhcp-66-92-183 ~]# host dhcp-93-194.nay.redhat.com Host dhcp-93-194.nay.redhat.com not found: 3(NXDOMAIN) add such line to /etc/hosts can make virt-v2v happy and do conversion as expected: ------------------------------------ --- old/etc/hosts 2010-07-29 13:00:36.205836872 +0800 +++ new/etc/hosts 2010-07-29 13:00:54.113089412 +0800 @@ -1,3 +1,4 @@ 10.66.92.183 dhcp-66-92-183.nay.redhat.com 127.0.0.1 localhost.localdomain localhost ::1 dhcp-66-70-198.nay.redhat.com localhost6.localdomain6 localhost6 +10.66.93.194 dhcp-93-194.nay.redhat.com ------------------------------------ Version-Release number of selected component (if applicable): virt-v2v-0.6.1-2.el6.x86_64 libguestfs-1.2.7-1.21.el6.x86_64 How reproducible: always Steps to Reproduce: 1.Make sure the Xen host with only rDNS 2.# virt-v2v -ic xen+ssh://xen_host -o rhev -osd 10.66.xx.xx:/vol/export domain_name Actual results: V2V doesn't begin conversion without any error msg, so it hangs there. Expected results: V2V can convert VMs via xen+ssh even the host with only rDNS, or at least pop up error MSG. Additional info: