Beyond The Data
[Installation:]
1. using opensuse 13.1 image from http://www.opensuse.org
openSUSE-13.1-DVD-x86_64.iso
2. format iso to bootable, ignore the warnings.
# isohybrid openSUSE-13.1-DVD-x86_64.iso
Warning: more than 1024 cylinders (4361).
Not all BIOSes will be able to boot this device.
3. write image to the flash-disk.
# cat openSUSE-13.1-DVD-x86_64.iso > /dev/sdb
4. using the flashdisk to boot T430, cleanup current partition tab, taking up full disk.
Done.
Just hit such a case, mis drop the folder “/bin”.
Enterprise Linux Enterprise Linux Server release 5.7 (Carthage)
Linux 2.6.32-100.37.1.el5uek
os still work. just /bin/ tools no longer functioning, no new access as “/bin/bash” not available.
#Solution.
Now what can be used: scp, vim .. and others in /usr/bin/
Lucky, to find a similar configured box, which should be the same packages version level or lower.
Im using :coreutils-5.97-23.el5
tried to find a box using :coreutils-5.97-23.el5_4.2
##
[root@box09 bin]# scp -r ractest@box06:/bin/ /
##
the bins with a bit lower version works fine within current os, as current platform libs provide a compatible runtime.
to solve the problem completely, run #yum update/reinstall to replace all binaries.
Regards,
-suse
this post also works for Redhat EL5 compatible.
My Configuration:
Host: testbox 2.6.18-128.2.1.4.37.el5xen EL5.7
Gust: testbox-vm1 2.6.18-348.el5 EL5.9
Steps:
1. on Host, enable dumps and restart xend service.
[root@testbox xen]# vi /etc/xen/xend-config.sxp
enable dump:
(enable-dump yes)
restart xend service:
[root@testbox xen]# service xend restart
As the root part on my box doesnt have enough space(2G+) for crash cores. using following link
[root@testbox 21_testbox-vm1]# rm -fr /var/xen/dump/
[root@testbox 21_testbox-vm1]# ln -s /var/ovs/mount/CC94A2F6CC2A4FD2957BB3FE6B6BA694/suse /var/xen/dump
2. change vm1 guest cfg file.
[root@testbox running_pool]# pwd
/var/ovs/mount/CC94A2F6CC2A4FD2957BB3FE6B6BA694/running_pool
[root@testbox running_pool]# cd 21_testbox-vm1/
[root@testbox 21_testbox-vm1]# vi vm.cfg
enable:
on_crash = ‘coredump-restart’
on_reboot = ‘restart’
shutdown vm using cmd: (If the box is not yet created, no need to shutdown, just create a new.)
xm shutdown 21_testbox-vm1
restart vm using new cfg:
xm create 21_testbox-vm1 -f ./vm.cfg
3. inside vm1.
enable sysrq:
kernel.panic_on_oops=1
kernel.panic=1
kernel.sysrq = 1
choosing RH compatible kernel, instead of the UEK kernel for dumps.
--OEL5 UEK kernel not working well with xendump service.
[root@testbox-vm1 ~]# vi /etc/grub.conf
default=1 <– the # of RH kernel
We are now using kernel:
kernel-2.6.18-348.el5
Install following RPMs for further cases:
kernel-debuginfo-2.6.18-348.el5
kernel-xen-2.6.18-348.el5
kernel-debuginfo-common-2.6.18-348.el5
reboot the guest, root access and issue:
[root@testbox-vm1 ~]# echo c >/proc/sysrq-trigger
a new core was generated in Host:
[root@testbox dump]# pwd
/var/xen/dump
[root@testbox dump]# ls
2014-0219-0905.44-21_testbox-vm1.49.core
4. how to analyze the core.
scp the core into testbox-vm1. for example:
(there should be some other ways to share files between guest/host, like via NFS)
[root@testbox-vm1 0013]# pwd
/var/crash/0013
[root@testbox-vm1 0013]# ls
2014-0219-0905.44-21_testbox-vm1.49.core
issue crash utility:
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[root@testbox-vm1 0013]# crash /usr/lib/debug/lib/modules/2.6.18-348.el5/vmlinux 2014-0219-0905.44-21_testbox-vm1.49.core crash 6.0.4-2.0.3.el5 Copyright (C) 2002-2012 Red Hat, Inc. ... This GDB was configured as "x86_64-unknown-linux-gnu"... KERNEL: /usr/lib/debug/lib/modules/2.6.18-348.el5/vmlinux DUMPFILE: 2014-0219-0905.44-21_testbox-vm1.49.core CPUS: 4 DATE: Wed Feb 19 08:36:35 2014 UPTIME: 00:02:14 LOAD AVERAGE: 0.20, 0.14, 0.05 TASKS: 131 NODENAME: testbox-vm1 RELEASE: 2.6.18-348.el5 VERSION: #1 SMP Wed Jan 9 08:26:59 PST 2013 MACHINE: x86_64 (2933 Mhz) MEMORY: 2 GB PANIC: "SysRq : Trigger a crashdump" PID: 2850 COMMAND: "bash" TASK: ffff81007fbc40c0 [THREAD_INFO: ffff81007edb8000] CPU: 0 STATE: TASK_RUNNING (SYSRQ) crash> bt PID: 2850 TASK: ffff81007fbc40c0 CPU: 0 COMMAND: "bash" #0 [ffff81007edb9d30] xen_panic_event at ffffffff8824e9c9 [xen_platform_pci] #1 [ffff81007edb9d60] notifier_call_chain at ffffffff80067565 #2 [ffff81007edb9d80] panic at ffffffff80093ec1 #3 [ffff81007edb9e70] sysrq_handle_crashdump at ffffffff801bdaee #4 [ffff81007edb9e80] __handle_sysrq at ffffffff801bd897 #5 [ffff81007edb9ec0] write_sysrq_trigger at ffffffff80110253 #6 [ffff81007edb9ed0] proc_reg_write at ffffffff8010c0f7 #7 [ffff81007edb9f10] vfs_write at ffffffff80016b4e #8 [ffff81007edb9f40] sys_write at ffffffff80017417 #9 [ffff81007edb9f80] tracesys at ffffffff8005d29e (via system_call) RIP: 00000036d80c72a0 RSP: 00007fffa5c209d8 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: ffffffff8005d29e RCX: ffffffffffffffff RDX: 0000000000000002 RSI: 00002ac118cab000 RDI: 0000000000000001 RBP: 0000000000000002 R8: 00000000ffffffff R9: 00002ac1156d4f50 R10: 0000000000000065 R11: 0000000000000246 R12: 00000036d8353780 R13: 00002ac118cab000 R14: 0000000000000002 R15: 0000000000000000 ORIG_RAX: 0000000000000001 CS: 0033 SS: 002b crash> |
[Test:]
[suse@suse ~]$ssh root@testbox-vm1
[root@testbox-vm1 ~]# echo c >/proc/sysrq-trigger
a new core (sizeof 2G, memsize of the guest vm1) is generated in testbox:/var/xen/dump
[Reference:]
How to enable automatic core dumps of xen guests?
Core dump Xen domU/guests
On new EL6 box, by default access auth policy is required to access firewall setups from remote(even ssh from root@localhost).
solution, 1. access root from local by sudo/su.
solution,2. add remote access policy file.
Sample:system-config-firewall from remote machine
[Error: ]
Cisco anyconnect failed:
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/opt/cisco/vpn/bin> ./vpn Cisco AnyConnect VPN Client (version 2.5.6005) . Copyright (c) 2004 - 2010 Cisco Systems, Inc. All Rights Reserved. >> state: Disconnected >> notice: Ready to connect. >> registered with local VPN subsystem. >> state: Disconnected >> notice: Ready to connect. VPN> conn myaccess.myserver.com >> contacting host (myaccess.myserver.com) for login information... >> notice: Contacting myaccess.myserver.com. VPN> >> Please enter your username and password. Username: [suse_me] Password: >> notice: Please respond to banner. ... ... accept? [y/n]: y >> state: Connecting >> notice: Establishing VPN session... >> notice: Checking for profile updates... >> notice: Checking for product updates... >> error: AnyConnect was not able to establish a connection to the specified secure gateway. Please try connecting again. >> notice: Connection attempt has failed. >> state: Disconnected |
failed anytime at the final step.
[root cause:]
the root cause is the xattr setting on /etc/resolv.conf
I was using pppoe connection last days, and setting /etc/resolv.conf with a fixed value.
cisco anyconnect will try anyway to replace/update items in /etc/resolv.conf. failed if no update permission.
I used “chattr +i ” to keep the file stable, but it failed to update and cisco anyconnect will give up connection at last.
[solution]
chattr -i /etc/resolv.conf