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Fresh 7 Error USB Hub Error

January 13, 2018, 11:06 am
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I did a fresh CentOS 7.1 minimal installation on my Intel PC which I plan to use for a server. The minimal installation went perfect but when I rebooted the server, I saw a USB hub error in yellow right before the login screen.

When I check the logs, I see the error:

[ 23.971561] hub 1-1:1.0: USB hub found [ 23.971583] hub 1-1:1.0: 4 ports detected [ 24.072927] usb 2-1: new SuperSpeed USB device number 2 using xhci_hcd [ 24.084141] usb 2-1: New USB device found, idVendor=0451, idProduct=4040 [ 24.084145] usb 2-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 24.084732] hub 2-1:1.0: USB hub found [ 24.085256] hub 2-1:1.0: config failed, hub doesn't have any ports! (err -19)

All the USB ports appear to work fine when I try and test/use them. I'd like to remedy / resolve this error.

The USB hub is USB 3.0 if that matters.

submitted by /u/cachedrive
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CentOS 7 disabling DST - Daylights Savings Time

January 14, 2018, 3:27 pm
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I need some correction in my understanding of my setup. There are a few servers that cannot be have Daylights Savings Time enabled. I'm creating a new ntp server on centos7 dedicated to these servers and disabling Daylights Savings Time, but I want this server to go to our corporate time server to maintain the correct sync time, but not Daylights Savings Time. Does this make sense?

I read online about doing a TZ database. Using these commands:

cd /etc

rm localtime

ln -s /usr/share/zoneinfo/Etc/GMT-8 localtime

I read about GMT vs UTC. Does anyone have a preference in the states?

submitted by /u/Jisamaniac
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Advice on Intel-SA-00088

January 14, 2018, 12:20 pm
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I'm working with my personal computer running Debian buster right now. I've got a path forward for work machines. The recommendation for remediating the Spectre and Meltdown vulnerabilities (just Meltdown right now, really) is to update to kernel 4.14.12-2, which is in the Debian sid tree as a source code package. I don't like to leave my system in such a way that it's a total pain in the ass to maintain, so I would like some advice on the recommended path forward.

I used to build custom kernels for FreeBSD all the time years ago, and they made the process pretty easy. I believe I've done it for Debian years and years ago as well. It's been a while now. I've already installed the firmware updates from Dell for Intel-SA-00086 (AMT vulnerability) and the Meltdown vulnerability. It still needs Intel microcode and/or kernel updates to redmediate the vulnerability. Should I build and run a kernel from the 4.14.12 source code or keep waiting for a release or backported 4.14 kernel to hit the Debian package tree? I'm trying to avoid ending up in depndency hell, and I'm a bit embarrassed to admit that it's been a long time since I've built a kernel from source.

Thanks in advance.

submitted by /u/Diffie-Hellman
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Cifs mount randomly failing with "input/output error"

January 14, 2018, 8:12 am
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Hi all,

I have a cifs mount that uses the following options:

//someserver/product /mnt/product cifs multiuser,sec=krb5,noperm,user=myuser,file_mode=0600,dir_mode=0700,vers=3.0

Mounting this works. However after a while I get an error as mentioned in the title. Now looking at dmesg, I see the following:

CIFS VFS: SMB signature verification returned error = -13

However I have no clue what this actually means. I've tried changing the vers parameter to 3.0, 2.1 and 1.0 but no improvement. The only thing that changed recently has been upgrading from kernel 4.11 to 4.14 and switching from no vers parameter to 3.0. Any ideas what could be wrong ?

EDIT: actually after switching back to smb1 i dont see this happening anymore. I also seem to not have that problem on all servers

submitted by /u/carlm42
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LPIC-3 304 study materials?

January 14, 2018, 8:21 pm
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Greetings fellow admins, if this is the wrong sub I do apologize, if it is please direct me to the correct sub!

My question is do anyone of you out there know where to find worthwhile resources for LPIC-3 304 studying? I have gone through the objectives but there isn’t necessarily any study material like there is for the LPIC-1 and LPIC-2 unless I am completely blind when looking through Amazon and the like.

If anyone has any resources I would be very grateful! Also to further expand on what I’m looking for I’m looking for study materials such as books, practice exams, etc

submitted by /u/Avaholic92
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weird yum question

January 14, 2018, 8:23 pm
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So I've got a pair of servers here baffling me. I'm likely to crack open a case with RH tomorrow, but I figured I'd post here in case anyone has a solution that I hadn't thought of.

So yum update is hanging with an Errno 12, which often means a bad rpm database. Just to be clear, I did a few things.

yum clean all (followed by yum update which responded the same) rm /var/lib/rpm/__*

yum clean all (again)

rpm --rebuilddb

Still nothing, but here's the weird part. I was under the impression that rpm --rebuilddb should recreate those __db* files, but they are not there. When i run it with verbose output it looks like it's doing something . Lots of something (and even the right stuff) but the files are not created.

I also looked at typical yum stopping stuff like stale nfs mounts, etc. nada. I'm a little nervous that the files are not being created. I thought that's what that command did. And, of course, yum update is still hanging (mostly at the rpm_check_debug step). Insight would be appreciated.

submitted by /u/linuxphoney
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Securing a Samsung 850 EVO SSD for surplus

January 15, 2018, 9:28 am
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I've got an old 500GB Samsung 850 EVO SSD that I'd like to surplus. I've seen a lot of conflicting information about securing used SSDs for sale, and I have what is probably a dumb question. The product data sheet says these drives support AES-256 self encryption. Samsung published a whitepaper on this series which is no longer available on their website, but I found an exerpt floating around which said

AES encryption is always active on an 840 or 840 Pro Series SSD. In order to benefit from the encryption feature, however, the user must enable an ATA password to limit access to the data. Failure to do so will render AES-encryption ineffective – akin to having a safe but leaving the door wide open.

Does this imply that the drives ship from the factory with an encryption key but no password, and that an ATA secure erase is sufficient to secure the drive to be surplussed even if we never set our own ATA password? hdparm reports 

Security: Master password revision code = 65534 supported not enabled not locked not frozen not expired: security count supported: enhanced erase 2min for SECURITY ERASE UNIT. 8min for ENHANCED SECURITY ERASE UNIT.

"not enabled" suggests that's not true, but only 8 minutes for an enhanced security erased suggests it is true since that wouldn't be enough time to zero out the entire drive.
Anyone know the deal with these drives? Or does anyone have an up-to-date and reliable resource about securing SSDs for surplus?

submitted by /u/redhat_noob
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Using a Yubikey for GPG and SSH

January 15, 2018, 9:04 am
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Server is stuck in a pxeboot loop. Finds kernel initrd and vmlinuz then reboots

January 15, 2018, 7:35 pm
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Hiya!

We are trying to upgrade our CentOS 6.9 server (Dell PowerEdge C6145) with bigger SSDs and are trying to do a fresh install over pxeboot. This client looks to an other server that hosts dhcp/dns/Foreman/tftp and kickstart scripts. Everything seems to be fine with all our services running. The problem occurs when the client begins pxe booting. It'll get an IP address from dhcp, find the linux kernels over tftp, load them, then immediately reboot where it will start the process all over. There are no other messages. I've tried changing the OS of the kernel that is loaded to CentOS 6.5, or CentOS 7.3, they all suffer the same issue (I get these kernels from mirror.centos.org and put them on my tftp server).

Every single time, this is the last thing I see before the screen blacks out, the system reboots, and the process starts all over again: https://i.imgur.com/EFxlGHn.jpg

There's no other warning messages. Any ideas on what I should fix?

pxelinux.cfg for client:

default linux label linux kernel boot/CentOS-6.9-x86_64-vmlinuz append initrd=boot/CentOS-6.9-x86_64-initrd.img ks=http://foreman:80/unattended/provision?token=0f6a663d-cfbf-4996-9822-2aaa5cdda9ff ksdevice=bootif network kssendmac IPAPPEND 2

Edit: I just tried a USB boot with CentOS 6.9 and the same exact thing happened. Loads initrd, loads vmlinuz, Probing EDD, reboots. Also, fyi, the server has an LSI RAID card, SAS2008-IR. Two of the drives are 1TB SSD for system. The remaining 4 are RAID 0. I don't think it matters but just adding that in case RAID cards can affect boot.

submitted by /u/polkaron
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Looking for a good book on Linux system administration

January 16, 2018, 2:59 am
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I am doing the course "Essentials of Linux System Administration (LFS201)" on Linux.com.
I like the course, but what I need is a good book next to it.
Does anyone know a good book on the subject of Linux System Administration?

submitted by /u/DontwakemeUp46
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unable to assign unix permissions to mounted drive.

January 16, 2018, 6:42 am
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My job just started using a Netapp as a file storage system and for some reason I am unable to assign group permissions (chmod/ chgrp) on the folders. I have the folders auto mounted so I can reach them but for some reason when I try and change the ownership of the folder it doesn't recognize the groups/user. I'm not sure if this is on the netapp side or linux side. Thanks in advance

submitted by /u/Mazurke
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Just had the "Open Source is for playing with, not for business" conversation with my boss

January 15, 2018, 8:06 pm
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What is this, 1997?

This comes about as I'm deploying Moodle for some online training we are doing. Yes, Postgres, Linux, and MySQL -- who really uses that stuff? And yes, Moodle may not match 100% of our requirements in the long run, but which will be cheaper -- hiring someone to write a Moodle extension, or hiring someone to write an entire LMS from scratch?

submitted by /u/bodangren2
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Clustering , high availability , load balancing ? How do to these

January 16, 2018, 9:32 am
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Hey,
I'm it guy with decent linux knowledge as user, and im looking to expand my knowledge. so my company has 10 abandon servers with decent spec , and im looking to learn how to do "Clustering , high availability , load balancing" with them but i don't know where to start or how i can make the environment like the real deal? What tools/products should i use? i don't have money to pay for courses or such, and the system admin in my company is a nice guy but not that nice to teach me, im just poor fella
Thank you in advance

submitted by /u/Newbi8283
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[Jenkins] how does a job got triggered?

January 16, 2018, 10:17 am
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I got jenkins setup. I have a test job call test. All it does it echo foo. For simplicity, there's no trigger, only manually hitting build now via the gui.

Can anyone explain to me how the job works? Is there a file get queued somewhere and then get executed?

The reason I ask this is because I have two jenkin box and i want the second jenkin box to mirror what the first jenkin box is doing with a small time delay. I was wondering if there a file created somewhere when you hit build now. Where I can rsync cron it over to the second jenkin box to trigger the job.

submitted by /u/juniorsysadmin1
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What do you use to capture, organize your important things and tricks?

January 16, 2018, 12:06 pm
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I wanted to ask you how you organize your notes and tricks. I mean things typically computer, some syntax, commands, maybe scripts. For some time I have been looking for some to add to my server and three things in one place. Very populatny of what I see is Evermote but maybe you have some other nice solutions on your own servers?

submitted by /u/TheBocios
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Question for the group around LFCS

January 16, 2018, 7:10 pm
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My boss has agreed to pay for LFCS. I have probably what I would consider intermediate linux knowledge currently. What I'm trying to decide is if I should book the test and focus on CentOS or Ubuntu? I work in a data center currently that has a lot of RedHat - so does that mean I should go CentOS? Is Ubuntu server more prevalnet elsewhere? Does it really matter that much even?

Thanks in advance, sorry if its a stupid question.

submitted by /u/bigdizizzle
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Better career move; learning Openshift or bare bones kubernetes?

January 17, 2018, 5:05 am
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I'm currently at a crossroad and need everyone's advice.

I want to move into the container development, management, and orchestration world out of interest and curiosity but I don't know which path to take.

I know Openshift is a platform built on kubernetes, but in terms of job prospects, would it be better to specialize on a kubernetes specific platform or just go right into bare bones kubernetes?

I'm RHCE certified if that makes any difference, so there's a reason to pursue Openshift there

submitted by /u/livintx
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Can anyone name a good tutorial/starting point for looking into MariaDB clustering/replication?

January 16, 2018, 5:52 pm
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Hi, I'm looking for a tutorial, or any starting point to look into replicating/clustering MariaDB/MySQL servers. I'm starting an apprenticeship in IT in summer and wanted to have a look into that topic for fun.

submitted by /u/niemalsnever
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Galera, Centos 7.4 x86_64 questions (setup is working)

January 17, 2018, 2:41 pm
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Hi there.

Just fiddling around getting galera working on two servers. It's now running fine, albeit with selinux disabled. Will fiddle with that.

Meantime, I have a question. to get the master node (server1) started, I go "galera_new_cluster", on the other box (server2) I go "systemctl start mariadb".

Now. Say I need to reboot server1. I go to server2 and systemctl stop mariadb. Probably the same on server1. I reboot the server.

Once it's rebooted, I'm probably getting errors about restarting the mariadb service from systemctl. So I assume I systemctl disable mariadb. I need to run galera_new_cluster again. And only at that point do I systemctl start mariadb on server2.

A bit messy, the restart of the service process. Has anyone tidied this process up? What did you do? Or have I got it completely wrong?

submitted by /u/Laurielounge
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Need help fixing a permissions issue

January 17, 2018, 3:26 pm
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So i did a terrible thing. I was trying to set permissions and not knowing what i was doing i did: chmod -R 777 /*

This did something weird to the system and now i cannot login as root or even use sudo. Anyone have any idea how to fix this?

This is Debian if that makes any difference.

submitted by /u/newITuser
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