Newest centos Questions

Q&A for system and network administrators

Centos additions to /etc/crontab not being executed [duplicate]

Ive added some lines to /etc/crontab and for some reason they aren't getting executed. To test this out I created a simple PHP script. I have executed this manually, so i know it works. $file = ...

sftp connection can't be established remotely

I'm trying to create a SFTP connection to a remote CentOS v6.8 webserver. When i connect through SFTP from my office network i can connect without any problems but when i try it from a different ...

pings ignored across VPN with Centos 7

I'm trying to setup a CentOS 7 DNS server in a VPN. I can't get devices from the VPN subnet (different subnet) to ping servers. I can get pings to work between servers (same subnet) When I run ...

CentOS 7 Using samba to connect to a windows share at boot

I'm trying to get a CentOS7 host to mount a directory shared on a Windows 2012 R2 server whenever the host boots. I have shared the directory to "Everyone" and other windows systems are mapping it ...

MySQL is using too much CPU

I have i7 3770 dedicated server with 32GB ram, and Centos7 is installed, below are CPU details [root@server ~]# lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: ...

Unable to access CentOS 7 Postgresql Server from another CentOS7 using PHP and PDO

The Beginning Server 1 is my CentOS 7 production server. It contains Apache, ssh and a Postgresql database. Server 2 is my CentOS 7 test server. It contains Apache, ssh and a test database. Both ...

Azure resize VM from A2/3 to DS2 v2

I'm trying to resize a couple of Azure VMs created some time ago from basic A3 and standard A3 to standard DS2v2. I don't seem to have the ability to resize to that size of VM. It would be a bit of a ...

How to map PHP module name with corresponding rpm package name on Centos?

I'm often provided a list of PHP modules as requirements for a given web application I need to setup on a server, and I find it sometimes tedious to find the corresponding RPM package name that I need ...

Best way to do a MySQL based Reverse Proxy [on hold]

I have one server which will act as the reverse proxy, and it should proxy the request to another server based on the requested domain and a MySQL table containing them. For example, let's say the ...

sudo: syntax error after running ./stack.sh (devstack)

The issue is coming while installing devstack for openstack. Before running "./stack.sh" sudo was working fine, but after running this is happening:- [root@localhost ~]# sudo sudo: >>> /etc/...

Ganglia unable to create tcp accept channel receiving NaN on graphs

Just recently, I started receiving errors for Ganglia and now on my graphs I am seeing NaN for all of the nodes except for one of them. The node that doesn't have the NaN issue is the one hosting the ...

EXIM debugging option “debug_print” unknown

How do you get exim on centos to debug? option "debug_print" unknown ("driver" must be specified before any private options) remote_login: debug_print = "This is a test" driver = plaintext ...

OpenVSwitch Create Tagged uplink to Firewall VM

I have installed OpenVSwitch with libvirt and added my VMs interfaces to the bridge. I set the VLAN Port on the second VM with ovs-vsctl set port vnet1 tag=2. I want to set the Port on vnet0 (which ...

CentOS 7 PV images?

I'm trying to install CentOS 7 under Xen as a PV DomU, but I can't find the needed initrd.img and vmlinuz images. Is there anywhere that I can download them, or if I need to, how can I generate them? ...

How do I list all new accounts created on CentOS Linux 7.2.1511

I employed a freelancer to check my security on my server and as well as overcharging me he has behaved very unprofessionally; not outlining the work he did and indulging in sarcasm and arrogant ...
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Why is CPU usage somewhat “nicer” today than yesterday?

First post here from an eager learner more educated with front end. Please consider the following munin graph: Considering the general traffic the site on this box got today was the "same" as ...

Issue with high server load centos

I'm having some major issues with one of my servers. Server load is extremely high: load average: 142.28, 144.80, 139.6 The server is running Centos 6 and has a Perl image sharing script running on ...

Apache redirecting “new-site-url/wp-login.php” to “old-site-url/wp-login.php” [on hold]

I'm migrating all of my company's web content to a new server. The main content I'm moving is a multisite WordPress install that I was able to get up and running on the new server. Whenever I try to ...

Segmentation error while trying to connect to external database on centos 6.5

I have drupal installed on server A (frontend) and database on server B (backend).Since there is no DB on server A I don't have mysql binary installed on server A. But I have all the drivers /API ...

centos 6.8 will not boot - error is showing under logs

My server rebooted when SSH was not working it had crashed and now it's having trouble rebooting. I have been able to go through the rescue operating system to look into it and I have found these ...

Iptables and tcp attacks protection rules

My current iptables (only ipv4, ipv6 is turned off on this server) looks like this: -P INPUT DROP -P FORWARD ACCEPT -P OUTPUT ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -m conntrack --ctstate RELATED,...

Jupyterhub with selinux

I'm trying to deploy jupyterhub on centos 7 with selinux enabled. I choose sudospawner for creating new jupyter notebook servers. When i try to login to jupyterhub, selinux logs the following error an ...

SOLVED Spacewalk rhnreg_ks ssl certificate failed verification

Spacewalk 2.6 on CentOS7 Registering client: CentOS6.8 trying to register CentOS client with # rhnreg_ks --serverUrl=https://YourSpacewalk.example.org/XMLRPC --sslCACert=/usr/share/rhn/RHN-ORG-...

Configure multiple ip on same vlan on centos 7 machine

My existing network file looks like below # cat ifcfg-ens1.200 DEVICE=ens1.200 BOOTPROTO=static ONBOOT=yes IPADDR=172.16.2.10 NETMASK=255.255.255.0 USERCTL=no NETWORK=172.16.2.0 VLAN=yes How to ...

iscsid.conf - What node.conn[0] stands for?

Greeting, I searched it on the uncle Google, however failed to find a true meaning for that phrase wich is stated within configuration file by default. [root@iscsi-initiator~]# grep conn /etc/iscsi/...

'vmxnet3' is not a valid device model name despite having VMTools installed on CentOS 7

I am trying to use the 'VMXNET3' driver for my ESXi guest on KVM. I installed the VMtools as required but still got the 'invalid model name' error. My host OS: # cat /etc/*release CentOS Linux ...

Amazon EC2 CentOS Goes Down Every 5-7 Days [duplicate]

I have a strange behavior at one of my EC2 servers. It runs a basic LAMP stack and a Drupal site. The database of the site is small. From my understanding it should not cause any issues. However, ...

Which KVM supported OS to use for latest fedora?

On the latest CentOS which is 7.3 right now, the latest supported fedora in KVM is fedora 23. If I want to have a Fedora 25 guest, which OS should I then say it is? Generic64?

Issue with resolving domains on CentOS 6

I was having an issue with updating YUM and also issues with CURL. This led me to find issues with resolving: root@server [~]# host google.com ;; connection timed out; trying next origin ;; ...

Libvirt host to virtual network

Environment: CentOS 7 + libvirt (with virt-manager) 6 NIC Multiple internal private networks Task: Create a virtual firewall and assign all NIC to it Problem: How can I connect the host system to ...

Server running at high CPU usage (100%)

I have a nginx server on a digital ocean droplet, with 2 CPU's and 4gb mem. I'm running a couple of minor WP-sites, without much traffic - but it seems like i can push the server to 100% CPU without ...

rsync with non-standard port and multifactor 2FA with Google Authenticator

SSH to my server works. But I've enabled Multifactor authentication with Google Authenticator. So during the process of SSH, it asks for my verification code. Issue now is I want to rsync to this ...

I want to use the whole space 20GB ( /dev/vda ) to partitions 10GB ( /dev/vda1 )

I want to use the whole space 20GB ( /dev/vda ) to partitions 10GB ( /dev/vda1 ) [root@server ~]# sudo ssm list -------------------------------- Device Total Mount point ----------------------...

Where do https accesses get logged in Tomcat 9?

I'm running Tomcat 9 standalone and I believe I am configured correctly for a secure connection to port:8443. If I make a connection to http://mysite I see the connection attempt in the ...

How to forbit apache httpd from adding headers to responses

I've a jetty server behind an apache httpd server. I properly handle headers to be returned to requests I receive at jetty level. But sometimes apache httpd add some headers (typically the Content-...

Unable to create an admin user with chef-server?

I want to configure chef-server over Centos 7, I installed the chef-server-core, then I added this line to /etc/hosts 192.168.0.4 chef.example.com Then I put this command: chef-server-ctl ...

How do I pause postgrey?

If I use service stop postgrey, then I get errors in my maillog Mar 17 18:49:10 ip-172-31-15-65 postfix/smtpd[23543]: warning: problem talking to server postgrey/socket: No such file or directory Mar ...

How to open a port on CentOS 7 when firewallD is not running?

I am trying to set up PacketFence, but the switch is comunicating on ports 1812 and 1813. I had made a fresh install of CentOS 7 and now I need to open the ports - I did some research but everyone ...

After restarting the server Mysql does not start working

I did restart my server using # reboot command Then I tried to access the server panel which is CentOS webpanel I got this error Warning: obfuscated: No such file or directory in /usr/local/cwpsrv/...

How to remove 'update-alternatives' links on Linux

Sorry for asking this, but I cannot resolve such a simple issue for a few hours: I made a typo mistake in update-alternatives --install /usr/lib64/R/lib/libRblapack.so libRblapack.so /usr/lib64/R/...

CentOS 6.8 ip & ifconfig provide different results for IPv6

Am having a weird issue with my CentOS 6.8 I notice a difference between the results coming out of both commands ip -6 and ifconfig. ifconfig is showing more ipv6 addresses Also some applications don'...

install composer on cent os 6.5

I'm trying to install composer on my server centos 6.5 PHP Version 5.6.30 I tried it with this command curl -sS https://getcomposer.org/installer | php but I get this error PHP Fatal error: ...

Can't open port on Amazon EC2 instance

I have an API which I successfully hosted on Amazon AMI instance. I know that's for sure because I can use it locally using curl. Api hosted on port 8080. That's what I putted into cmd for open port: ...

Centos 7 Failed to start LSB: VirtualBox Linux Additions kernel modules [migrated]

Recently ran updates on one of my Centos 7 Development Environments (server) which is running though Parallels on Mac OSX, when I went to start the VM recently I received this output: [FAILED] Failed ...

Exim MySql Bug?

In an Authenticator for a outgoing smtp connection I have this: remote_login: driver = plaintext public_name = LOGIN client_send = : user : password And that works fine. If I switch out the ...

Linux install goes to blank screen [migrated]

I downloaded both latest Centos and Fedora ISO and burned onto CD using Imgburn. I then first booted up with Centos CD on my old HP DC5000 computer. It appears to boot to the CD just fine and gives me ...

Name resolution and DNS registration for a CentOS 7 Azure VM

I have a Linux VM (CentOS 7.2) running on Azure, which is configured as a DHCP client because this is required by the Azure platform; Azure DHCP correctly supplies a network configuration to the VM, ...
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Intermittent issues uploading via FTP (fatal: protocol version) - Connections not being removed?

Client is experiencing intermittent problems uploading files to the FTP server. Sometimes it works and sometimes it doesn't. It seems they can login ok (the vsftpd logs show successful logins), but ...

IBM WebSphere SDK Java Technology Edition Version 8.0 for Liberty install error using IBM Installation Manager on CentOS6.8

The "packages" in the error below means that result of ./imcl listInstalledPackagescommand? If the question above is correct, I should install one of liberty package using "IIM" right? ERROR that ...

Libreswan based VPN not establishing L2TP tunnel after IPSEC authentication

I have been trying to setup a libreswan VPN client on a CentOS machine to connect to a libreswan VPN server (also CentOS) for the past few days but without success. The problem is as follows: - VPN ...
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