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Category Misc

Failed to start crond.service: The name org.freedesktop.PolicyKit1 was not provided by any .service files

Sometimes you might come across some errors as follows, when you start services in servers.

Failed to start crond.service: The name org.freedesktop.PolicyKit1 was not provided by any .service files 

Nothing to worry, it could just be because you don’t have the proper permission to do so, or you failed to add a ‘sudo’ infront of the command. Juts try with sudo and it will work.

[abc@greproot ~]$ sudo systemctl start crond.service
[abc@greproot ~]$ sudo systemctl status crond.service
● crond.service – Command Scheduler
Loaded: loaded (/usr/lib/systemd/system/crond.service; enabled; vendor preset: enabled)
Active: active (running) since Thu 2020-05-28 10:29:05 UTC; 10s ago

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Create local yum repo in Centos7

To create a local yum repo, all you need to do is to make sure the packages are available in a path in the server, say /downloaded_packages/

Now, create a repo file. Be default, all repo files are present in the path /etc/yum.repos.d/ . I am going to name my repo as local_yum, so I will create a repo file named local_yum.repo and add the following contents in it.

cat /etc/yum.repos.d/local_yum.repo

[local_yum]
name=local_yum
baseurl=file:///downloaded_packages/
gpgcheck=0
enabled=1

The above files tells the programme to take the packages from the baseurl mentioned in the file, which in our case is our local folder /downloaded_packages/

Now check if our repo is listed correctly. In my case, I have not set any other repos, so only my local repo is listed...

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Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.39/containers/nginx/json: dial unix /var/run/docker.sock: connect: permission denied

I was getting this error when I was trying to run a docker container using jenkins declarative pipeline script. This was being run on my localhost and below is what I needed to correct it.

Added jenkins user to docker group

sudo usermod -a -G docker jenkins

The solution that actually worked was to change the permission of the sock file to 666

devops-04:~$ ls -al /var/run/docker.sock
srw-rw—- 1 root docker 0 Oct 28 11:54 /var/run/docker.sock

devops-04:~$ sudo chmod 666 /var/run/docker.sock

devops-04:~$ ls -al /var/run/docker.sock

 

Once this was done my pipeline script started working!

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Install PHP7.2 on Centos7

PHP 7.2 does not come by default with Centos base repo. Hence, in order to install it we first need to install and enable the remi repo and then install PHP. Execute the following commands in the below order to get PHP 7.2 installed on Centos7.

[root@de56f5fc317d ~]# yum update

[root@de56f5fc317d ~]# yum install yum-utils

[root@de56f5fc317d ~]# yum install epel-release

[root@de56f5fc317d ~]# yum install http://rpms.remirepo.net/enterprise/remi-release-7.rpm

[root@de56f5fc317d ~]# yum-config-manager –enable remi-php72

Now, check if PHP 7.2 packages are available.

[root@de56f5fc317d yum.repos.d]# yum list available php72
Loaded plugins: fastestmirror, ovl
Loading mirror speeds from cached hostfile
* base: centos.mirrors.nublue.co.uk
* epel: lon.mirror.rackspace.com
* extras: mirror...

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Securing Solr Admin Console

The solr admin console, by default, is not secured or password protected. Anyone with the link can access all the details in the console. This post describes the steps required to secure the console. The post assumes that you followed the steps in the following two posts to

  1. Install Java and Jetty in the server
  2. Install Solr in the server

Our jetty installation is at /opt/jetty which is our java web server. Our solr installation is at /opt/solr which is our search platform.

We need to modify the following three files in order to secure the admin console.

  1. /opt/jetty/etc/jetty.xml
  2. /opt/jetty/etc/webdefault.xml
  3. /opt/jetty/etc/realm.properties

If you are not sure which files are to be edited, run the following command in the server and check for java_home variable...

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Install solr with jetty in Ubuntu

Solr is a search platform which is built on Apache Lucene. It makes search easier and faster. Solr can be installed along with tomcat or jetty. This post explains the installation based on jetty.

First you should install java and jetty as mentioned in the link here.

We will install solr also in /opt. First download the latest version of solr from https://archive.apache.org/dist/lucene/solr/

I am going to download version 4.10.4. Once downloaded, uncompress it and copy the war file from dist directory to jetty webapps folder.

[root@test ~]#cd /opt

[root@test ~]# wget https://archive.apache.org/dist/lucene/solr/4.10.4/solr-4.10.4.tgz

[root@test ~]# tar -xzvf solr-4.10.4.tgz

[root@test ~]#cp  solr-4.10.4/dist/solr-4.10.4.war   /opt/jetty/webapps/solr.war

Now, a few more files need to be ...

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Installing Jetty in Ubuntu 14.04

Jetty is a java web server like tomcat, and java servlet container. This post describes how to install the latest version of Jetty in Ubuntu.

Latest version of Jetty can be downloaded from http://download.eclipse.org/jetty/stable-9/dist/

Jetty requires java and hence the first step is to install java. The latest version of Jetty, as of this writing is Jetty 9.3.8. Check the link here which shows what version of Java is required for the version of Jetty you are installing. If the version of Java does not match the version in which Jetty is compiled, then it will result in version conflict and Jetty will fail to start.

I am going to install Jetty 9.3.8, hence I need JVM 1.8. Login to your ubuntu machine and switch to root. Then issue the following commands to install java in the server.

[ro...

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CSF on SolusVM Node

One of my clients wanted to secure their slave nodes with a firewall, and asked to install CSF on the servers. We setup a new slave node and installed CSF and everything was working fine. Created a new VPS, and noticed that the VPS IP Address is not responding. There was no ping to the VPS IP Address from outside. Logged into the server via console and the IP Address was up in the server. However there was no inbound and outbound network connections.


[root@vps ~]# ping google.com

Thinking it could be a resolver problem, I switched the resolver entries to use google DNS as follows.


[root@vps ~]# vi /etc/resolv.conf

Enter the following

nameserver 8.8.8.8
nameserver 8.8.4.4

Save and quit the file. Tried to ping google.com again from the server and it timed out again...

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Solusvm Access Denied !

I was working on my client’s solusvm admin panel that I got kicked out suddenly. I started getting the following message, whatever way I tried to access the admin control panel.


Access Denied! Contact the system administrator for support

I tried various ways to gain access, but nothing worked. The following trick helped me.

I logged in to the server as root via ssh and whitelisted my IP Address.


[root@abc ~]# cd /usr/local/solusvm/tmp/
[root@abc ~]# touch fixwhitelist
[root@abc ~]# chown solusvm.solusvm fixwhitelist
[root@abc ~]# vi fixwhitelist

Then enter your IP Address in that file, save and restart solusvm.

[root@abc ~]# /etc/rc.d/init.d/solusvm restart
Stopping solusvm: [ OK ]
Starting solusvm: [...

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Hetzner server with > 2TB disk

Recently I ordered a Hetzner server for one of our clients. The server had two 3TB disks. Hetzner provides a command line installation of the desired OS once we login to their server. As such, I logged in to the server and installed Centos6 by executing “installimage” option as suggested by Hetzner.

After installing OS and rebooting the server, I noticed that the 3T disk is not showing full space.

[root@abc ~]#df -h
Filesystem      Size  Used Avail Use% Mounted on
/dev/sda3        99G  2.5G   91G   3% /
tmpfs           463M     0  463M   0% /dev/shm
/dev/sda2       976M  126M  800M  14% /boot

/dev/sda4   2.3T     123M   2.2T  1% /home

If the disk size is greater than 2T you cannot use normal fdisk to create partition...

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