My Adventures in Coding

November 21, 2016

VirtualBox – Resize a CentOS Virtual Drive

Filed under: CentOS,Linux,VirtualBox — Brian @ 9:51 pm
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Recently I created a CentOS VM using VirtualBox for some development work I was doing, but foolishly I set the virtual disk to the default size of 8 gigs, figuring it would be easy to resize it later.

Well, after piecing together bits of information from several places I was finally able to get my virtual disk resized as well as my CentOS partition that was on it. Here are the steps that worked for me!

Expand VirtualBox Drive

The first thing you need to do is expand your virtual drive which I did using the VBoxmanage command line tool provided by VirtualBox (reference).

Note: Ensure virtual box root folder is on your path (e.g., C:\Program Files\Oracle\VirtualBox).

Resize the partition with the command VBoxmanage to the desired size in megabytes (e.g., here I am resizing the drive to 20 gigs):

VBoxmanage modifyhd MyCentosDisk.vdi --resize 20000

Resize Partition with GParted

Download the gparted live cd.

Attach the gparted live cd as a drive to your virtual machine and make it the “Primary Master”.

Note: Ensure the checkbox “Live CD” is selected when you add the CD drive.

Now start your VM.

The gparted UI will load. Now resize the parition by expanding it to use the available free space on the virtual disk.

Shutdown your VM, remove the gparted live cd drive and set your virtual disk to once again be the “Primary Master” drive.

However, after you restart your VM you will notice that CentOS is still not aware of the additional space:

df -h

Expand CentOS Partition

Now you will need to expand your Linux partition to use the free space on the drive.

First check the sizes of the current partitions and get the name:

vgdisplay -v

On my system the name of the partition to expand was “/dev/centos/root”.

Extend the volume with the available free space:

lvextend -l +100%FREE /dev/centos/root

Now you are ready to perform the online resize:

xfs_growfs /dev/centos/root

NOTE: resize2fs works on other distributions of Linux but not on CentoOS, so you must use xfs_growfs (reference).

I hope that helps!

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April 3, 2016

Jetty – Setup Jetty on CentOS 7

Filed under: Jetty,Linux — Brian @ 9:50 pm
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I recently setup Jetty on a CentOS 7 Linux server. Previously we had been running Jetty in a windows environment but now we are moving our servers over to Linux. Here are my setup notes, I hope they help!

Install JDK

Note: We are using the Oracle JDK (Not openJDK). Check for the latest version of JDK 1.8.

Download and install the JDK:

wget --no-cookies --no-check-certificate --header "Cookie: oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u111-b14/jdk-8u111-linux-x64.rpm" -O /opt/jdk-8-linux-x64.rpm

yum install /opt/jdk-8-linux-x64.rpm

Set JAVA_HOME and add it to your PATH:

Create a file in /etc/profile.d to store java settings:

sudo touch /etc/profile.d/java.sh

vi /etc/profile.d/java.sh
Add the lines:

export JAVA_HOME=/usr/java/latest
export PATH=$JAVA_HOME/bin:$PATH

Install Jetty Web Server

Note: Check for the latest version of Jetty.

Download and install Jetty:

wget http://central.maven.org/maven2/org/eclipse/jetty/jetty-distribution/9.3.14.v20161028/jetty-distribution-9.3.14.v20161028.tar.gz

tar -zxvf jetty-distribution-9.3.14.v20161028.tar.gz

mv jetty-distribution-9.3.14.v20161028 /opt/jetty-9.3.14

ln -s /opt/jetty-9.3.14 /opt/jetty

Note: creating a soft link for your /opt/jetty install will be very useful later when you want to upgrade your version of Jetty. All you will need to do to upgrade is just download the tar.gz of the newest version, unpack it, and point the soft link to the new folder.

Create a temp folder for Jetty to unpack war files:

mkdir /opt/temp

Create webappbase folder where your apps will run:

mkdir /opt/webappbase

Move start.ini and webapps into the webappbase folder:

mv /opt/jetty/webapps /opt/webappbase/webapps

mv /opt/jetty/start.ini /opt/webappbase

Create a “jetty” user that Jetty will run under:

useradd -m jetty 

Update files and folders to be owned by “jetty” user:

chown -RH jetty:jetty /opt/jetty
  
chown -R jetty:jetty /opt/webappbase
  
chown -R jetty:jetty /opt/temp

Configure Jetty Web Server

Setup Jetty as a service:

ln -s /opt/jetty/bin/jetty.sh /etc/init.d/jetty

Add the new Jetty service to be managed by chkconfig:

chkconfig --add jetty

Set Jetty service to run on startup for the following run levels:

chkconfig --level 345 jetty on

Create a jetty settings file:

sudo touch /etc/default/jetty

You will need to set TMPDIR, JETTY_BASE, and JETTY_HOME. Also, any JAVA_OPTIONS you need to set can be set in the settings file for your Jetty server.

Add jetty settings by editing the jetty default settings file:
vi /etc/default/jetty

TMPDIR=/opt/temp
 
JETTY_BASE=/opt/webappbase
 
JETTY_HOME=/opt/jetty

JETTY_USER=jetty
 
export JAVA_OPTIONS="-Xms128m -Xmx2048m -server -XX:+UseConcMarkSweepGC -XX:+CMSClassUnloadingEnabled"

If you want to change the default port number, you can do so by editing the start.ini file:
vi /opt/webappbase/start.ini

# Replace 
# jetty.http.port=8080
# With 
jetty.http.port=8081

Start Jetty Server

Switch to the “Jetty” user, then start the Jetty service:

sudo su - jetty
service jetty start

Test that the server is running:

curl localhost:8081

Deploy a War file

To deploy an application to Jetty, all you need to do is copy a WAR file to the folder:

/opt/webappbase/webapps

That’s all!

December 22, 2011

Linux – How to ssh between two linux computers without needing a password

Filed under: Linux — Brian @ 10:44 pm
Tags: ,

Having to constantly type in your password on a linux server that you ssh to often can get to be an annoyance. Luckily this is an easy problem to solve. Since I always end up forgetting how to do this setup, I thought I would finally write this down, even if just for my own reference :).

1. ssh to server1

Connect to server1 and generate a public/private key pair.

 
ssh myusername@server1
password:
ssh-keygen -t rsa

When you run this command you will be prompted to answer several questions. Just hit enter each time until you are returned to a prompt.

Generating public/private rsa key pair.
Enter file in which to save the key (/home/local/myusername/.ssh/id_rsa): 
Created directory '/home/local/myusername/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/local/myusername/.ssh/id_rsa.
Your public key has been saved in /home/local/myusername/.ssh/id_rsa.pub.
The key fingerprint is:
15:68:47:67:0d:40:e1:7c:9a:1c:25:18:be:ab:f1:3a myusername@server1
The key's randomart image is:
+--[ RSA 2048]----+
|        .*Bo=o   |
|       .+o.*  .  |
|       ...= .    |
|         + =     |
|        S +      |
|         .       |
|      . .        |
|      E+         |
|      oo.        |
+-----------------+

Now you will need to copy the public key you just generated and save it somewhere, you will need it later. Also ensure when you copy the key that the text is all on one line, if there are line breaks in the text, it will cause problems later when you try and use the key.

cd .ssh
cat id_rsa.pub
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAyFS7YkakcjdyCDOKpE4RrBecRUWShgmwWnxhbVNHmDtJtK
PqdiLcsVG5PO94hv3A0QqlB1MX33vnP6HzPPS7L4Bq+5plSTyNHiDBIqmZqVVxRbRUKbP44BaA9RsW2ROu
8qdzmXRPupkyFBBOLa23RJJojBieFGygR2OwjS8cq0kpZh1I3c1fbU9I5j38baUK0naTBe2v7s/C8allnJ
hwkfds+Q9/kjaV55pMZIh+9jhoA8acCA6B55DYrgPSycW6fEyV/1PIER+a5lOXp1QCn0U+XFTb85dp5fW0
/rUnu0F9nBJFlo7Rvc1cMuSUiul/wvJ8tzlOhU8FUlHvHqoUUw== myusername@server1

2. ssh to server2

Now we will copy the public key from server1 to server2.

ssh myusername@server2
password:
mkdir .ssh
cd .ssh
vi authorized_keys
# paste the public key
chmod 600 authorized_keys

3. Test that your setup is working

ssh myusername@server1
password:
ssh myusername@server2
# you should not be prompted for a password!

That is all! (Thanks Dave!)

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