/ - rtt - IT Resource

  • Linux Permissions and Groups Real Usecase for Group Access


    I have a directory structure which the primary user needs full access on but wanted a user to access only a specific directory within the main directory (so they could write in there only and nowhere else). Here's what I did: [root@compevo8001 dllnow]# ls -alh drwxrwxr-x  2 someuser software  4.0K Oct 19  2017 ExpireYMD-2017-11-20 drwxrwxr-x  2 someuser software  4.0K Nov 19  2017 ExpireYMD-20........
  • Centos 7 - How To Install NFS and Mount Remotely


    1.) First install nfs-utils [root@bcitcourse ~]# yum -y install nfs-utils Loaded plugins: fastestmirror base                                                         &n........
  • Duplicate entry '2147483647' for key 'PRIMARY' MySQL Error Solution


    This usually happens when you are using something like an INT and try to insert a larger value than the maximum which is larger than "2147483647" On a practical term I have seen this and been guilty of this error when using scripts like PHP and generating large random numbers:   $hash = mt_rand(5,9999999999999); Obviously that many 9's are more digits than the maximum of an INT resulting in that error.  Change your code accord........
  • M2Crypto.SSL.Checker.WrongHost: Peer certificate subjectAltName does not match host, expected fedora-archive.ip-connect.vn.ua, got DNS:mirror.ip-connect.vn.ua


    You are using Centos 5 which is deprecated so nothing in yum will work until you follow this post to use the vault: http://realtechtalk.com/Centos_59_Working_Vault_Repo_file-1921-articles yum update Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * epel: fedora-archive.ip-connect.vn.ua Traceback........
  • DRBD Split-brain solution


    Uh oh [17925926.174277] block drbd0: Handshake successful: Agreed network protocol version 96 [17925926.174325] block drbd0: conn( WFConnection -> WFReportParams ) [17925926.174342] block drbd0: Starting asender thread (from drbd0_receiver [1682]) [17925926.174432] block drbd0: data-integrity-alg: <not-used> [17925926.174581] block drbd0: drbd_sync_handshake: [17925926.174586] block drbd0: self 2AAE66AF9252D6DB:2815BF........
  • Linux How To Recover Partition Table from Kernel and Restore Centos/Debian etc..


    We've all done this at some point, you work on the wrong shell window and this was my first time making this mistake but I deleted a partition table in fdisk, recreated it and saved it with "wq" and even ran partprobe!  If you haven't rebooted yet then you can still recover your partition table, otherwise you're in big trouble. Fortunately since it was a live system and in use the kernel still had to use the old table like below:........
  • Centos installing grub problems suspect gpt problem


    grub> root (hd0,0) root (hd0,0)  Filesystem type is ext2fs, partition type 0xfd grub> setup (hd0) setup (hd0) But if you do: root (hd1,0) setup (hd1) it does work, I think hd0/sda had a GPT partition that was not removed properly (what I did was just dd bs=512 count=1 the partition table from another drive since the partition table should be identical).  Checking if "/boot/grub/........
  • Centos 6 how to guide convert LVM non-RAID into mdadm 1/10 RAID array live without reinstalling


    Here is the scenario you or a client have a remote machine that was installed as a standard/default minimal Centos 6.x machine on a single disk with LVM for whatever reason.  Often many people do not know how to install it to a RAID array so it is common to have this problem and why reinstall if you don't need to?  In some cases on a remote system you can't easily reinstall without physical or KVM access. So in this case you add a second physical or disk or already ha........
  • openvz yum problem Centos 6.5 cannot find file on mirror:


    #solution Edit /etc/yum.repos.d/openvz.repo For the first two entries comment out #mirrorlist and uncomment #baseurl and then it worked openvz yum problem Centos 6.5 cannot find file on mirror: yum update Loaded plugins: fastestmirror Determining fastest mirrors  * openvz-kernel-rhel6: mirrors.ustc.edu.cn  * openvz-utils: mirrors.ustc.edu.cn base      ........
  • drbd won't sync 8.3.13 on OpenVZ kernel


    <p>I used the matching 8.3.13 utilities and it didn't work but strangely the newer 8.3.16 which makes DRBD complain works just fine.</p> <p>GIT-hash: 83ca112086600faacab2f157bc5a9324f7bd7f77 build by root@sighted, 2012-10-09 12:47:51<br /> &nbsp;0: cs:SyncSource ro:Secondary/Primary ds:UpToDate/Inconsistent A r-----<br /> &nbsp;&nbsp;&nbsp; ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:5236960<br /> &nbsp;&nbsp;&am........
  • yum error "Error: database disk image is malformed" solution


    yum -y install mathtools Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * base: centos.mirror.rafal.ca  * epel: mirror.steadfast.net  * extras: mirror.agmn.ca  * rpmforge: repoforge.mirror.constant.com  * updates: centosb5.centos.org extras                         ........
  • drbd howto solve splitbrain or WFConnection


    On primary node drbdadm connect all On secondary node drbdadm -- --discard-my-data connect all  ........
  • How to view GPT/EFI Windows Partition Table


    fdisk unfortunately can't do this and I'm not sure if there's any updated version that handles it but parted can do it. Here's an example of how to do it: parted /dev/sda print 1 17.4kB 1024MB 1024MB ntfs primary 2 1024MB 16144MB 15120MB ntfs primary /dev/sda1 would be the first partiton /dev/sda2 would be the second partition You can then just access them like any other normal partition.........
  • mdadm: /dev/sdb1 not large enough to join array solution


    mdadm --manage /dev/md1 --add /dev/sdb1 mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: metadata format 00.90 unknown, ignored. mdadm: /dev/sdb1 not large enough to join array md1's first primary member /dev/sda3 has 57394 cylinders while the /dev/sdb1 has 57393 (1 less cylinder) which is why it won't work.  fdisk -l /dev/sda3 Disk /dev/sda3: 47........
  • How to mount/access a single partition from dd image with Linux


     parted sdc.img GNU Parted 1.8.8 Using /home/one/sdc.img Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) unit                                                  &nb........
  • How to recover from dead DRBD partition/hard drive in two simple commands


    This assumes that you've at least created the correct partition for your DRBD already. Notice that I am "diskless", that's because either your DRBD partition doesn't exist/has been renamed (eg. sdb becomes sda when sdb dies and you reboot) or because that drive is really actually dead/gone. *If you need to permanently change the partition/device for your resource be sure to edit /etc/drbd.conf on both hosts and reload the config. (replace r0 with........
  • monit example tutorial how to enable status checking and manipulation


    You need to enable the httpd daemon with monit to actually view the status and control, it's not only for the web interface since the httpd is the ONLY way of controlling monit and viewing the status. monit monitor all will also reinstate disabled services if they've timed out too much.  Just restarting the service will do nothing to re-monitor a service that monit has stopped monitoring due to too many failures. *Also note that /etc/monit.conf i........
  • Ubuntu/Debian DRBD 8.0 Setup Guide


    I've only used it on Centos, so I thought I'd make a quick Debian guide: Install the DRBD Package apt-get install drbd8-utils Reading package lists... Done Building dependency tree       Reading state information... Done The following packages were automatically installed and are no longer required:   libswfdec-0.8-0 Use 'apt-get autoremove' to remove them. The following........
  • DRBD WFConnection Problem/Solution


    This has stumped me  a few times because I keep forgetting that Centos 5.5 comes with a default iptables configuration that ends up blocking DRBD traffic, I tried all the normal things and couldn't understand why I couldn't make my normal DRBD config work.  So if you have WFConnection problems and have tried the normal "mailing list" fixes, check your firewall status first! Both Nodes Say the Following: version: 8.3.8 (api:88/prot........
  • How To Set DHCP/Static IP Address in Centos/RHEL/Fedora & Debian/Ubuntu/Kubuntu/MEPIS Set DHCP/Static IP Address


    Basically the two main types of distros are Debian and RHEL/Centos based.  I'm just going to give a quick overview of how the configuration of IP interfaces works in Debian/Centos based distros. *Just one thing to remember, when setting IPs statically you have to manually specify a DNS server in /etc/resolv.conf (since DHCP is what normally does it automatically) Debian/Ubuntu/Kubuntu/MEPIS The IP (DHCP &........
  • Picking an FTPD (vsftpd) Server in Linux Centos/Debian


    I decided on using yum to help me decide even though I normaly use proftpd I decided to see what else I could find. yum search ftp Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile  * rpmforge: ftp-stud.fht-esslingen.de  * base: mirrors.netdna.com  * updates: updates.interworx.info  * addons: yum.singlehop.com  * extras: mirrors.netdna.com rpmforge   ........
  • GRUB Boot FreeBSD


    GRUB Boot FreeBSD[code:1:a7050277b7]title FreeBSD 6.0 root (hd0,2,a) kernel /boot/loader[/code:1:a7050277b7] Just insert the above code into GRUB's [b:a7050277b7]menu.lst[/b:a7050277b7] and make sure you set the root path correctly. [quote:a7050277b7]Let's quickly explain what the root (hd0,2,a) means: *hd0 stands for the primary master drive *2 stands for partition 3 *a stands for the........
  • FreeBSD Desktop OSs


    FreeBSD Desktop OSsI would probably choose these over Linux. In many ways these are probably more stable and just as easy to use as any Linux distros but the benefit of stable, updated and secure packages! PC-BSD - http://www.pcbsd.org DesktopBSD - http://www.desktopbsd.net/index.php?id=37 Personally PC-BSD is Beta at this point and is not easy if you are installing it on a non-primary partition. I have not used Deskt........
  • Create Table with structure of another existing table


    Create Table with structure of another existing tableOk, this has many valid uses such as if you need to create backups or the ability to undo changes, you would want to create new tables with the same structure as another. Here is how you do it. [i:7ed9581493] Also remember Indexes such as PRIMARY KEYS [b:7ed9581493]will not be preserved[/b:7ed9581493] so you will have to readd them manually.[/i:7ed9581493] [code:1:7ed9581493]CREATE TABLE NewName AS SEL........
  • ADD PRIMARY KEY to Table


    ADD PRIMARY KEY to TableHere is an example of readding a PRIMARY KEY with an AUTO_INCREMENT field: [b:40986c2a8b]First make the field NOT NULL[/b:40986c2a8b] [code:1:40986c2a8b] ALTER TABLE tableName MODIFY FieldNAME INT(18) NOT NULL; [/code:1:40986c2a8b] [b:40986c2a8b]Create The Primary Key[/b:40986c2a8b] [code:1:40986c2a8b]ALTER TABLE tableName ADD CONSTRAINT PRIMARY KEY(FieldName);[/code:1:40986c2a8b........
  • iPhone Backgrounder Adds True and Real iPhone multitasking on jailbroken phones


    Apple crippled the iPhone by not allowing multi-tasking of the non-primary apps.  I use SSH a lot and I don't want to close my session just to check my e-mail, etc, now an app found in Cydia called "Backgrounder" allows just that. Although it's not perfect, we installed the correct one for "3.x" iPhones and hit "Reload SpringBoard" and the hour/circle glass has just been going for minutes. It seems like it installed fine even with the crash t........
  • iPhone 3GS 32GB "Harsh Review"


    Yes, I admit I finally got bitten by the hype as much as I can usually see through it all.  Keep in mind this review is of the "stock" phone, no jailbreaking yet which is what really unleashes the customizability and why I bought iPhone. I had better things to say about this phone before buying it, and it is a great phone, perhaps the best on the market by far, if not because of the Mac OS port onto the iPhone and all the apps, etc, etc. With that said........
  • SSH Slow Login even with SSHD UseDNS no parameter


    I couldn't understand why on one system it took a few minutes to get the SSH login prompt when connecting to other systems. The other systems all had the UseDNS parameter set to no, which almost always resolves the login prompt delay. The reason is Ubuntu and perhaps Debian and other distributions /etc/nsswitch.conf file Edit yours to have the "hosts" line like so (notice that files and dns are the primary resolution choice........
  • ENOM Major Outage


    At this time we can't resolve Enom's website and all DNS requests to their 4 primary name servers are failing, although the hostnames themselves still resolve:    Name Server: DNS1.NAME-SERVICES.COM    Name Server: DNS2.NAME-SERVICES.COM    Name Server: DNS3.NAME-SERVICES.COM    Name Server: DNS4.NAME-SERVICES.COM    Name Server: DNS5.NAME-SERVICES.COM You would really think Enom, bein........
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