Searching in Splunk

When you are building the search criteria, click the field and value in the search result to add it to the search.

 

Wildcard character

  • * (asterisk) one or multiple characters

Exact phrases

  • Use ” (double quotes)

Search for quotes

  • \” (use backslash to escape quotes if you want to search for quotes)

Keywords in the search bar are case sensitive!

Boolean keywords are

  • AND (if omitted, it is implied)
  • OR
  • NOT

Order of boolean evaluation

  1. Inside parentheses ()
  2. NOT
  3. OR
  4. AND

Operators

  • =
  • !=
  • >
  • >=
  • <
  • <=

Examples

  • soourcetype=access_combined

Best search practices

Search in a time range

  • s  Seconds
  • m   Minutes
  • h  Hours
  • d  Days
  • w  Weeks
  • mon  Month
  • y  Year
  • @  Round down to the nearest unit

Examples

  • -30s  In the last 30 seconds
  • -30m@h  Round to the last hour. If the event was run at 5:42, events from 5:00 are returned
  • earliest=-2 latest=-1h  From two hours ago to one hour ago
  • earliest=05/12/2017:12:00:00  From an absolute date and time

Indexes

If the data is organized by multiple indexers, specify the index where the data is stored

Examples

  • index=main

Splunk installation

Install Splunk

  1. Navigate to the Splunk website at splunk.com,
  2. In the upper right corner select the Free Splunk button,
  3. If you don’t yet have a Splunk account, register to create one, otherwise log in,
  4. Select the Free Download in the Splunk Enterprise frame,
  5. Select the tab with the operating system of your machine.

Linux

  1. The simplest way to install Splunk on Linux is with wget in the command line. Click the Download via Command Line (wget) in the upper right corner in the Useful Tools box.
  2. Copy the command to your clipboard from the popup window,
  3. Execute the wget command in a terminal window to download the tar archive,
  4. It is recommended to install Splunk in the opt directory, untar the archive there.
    sudo tar xvzf splunk.tgz –C /opt

Windows

  1. Download the .msi installer for your operating system (32 bit or 64 bit),
  2. Run the installer, follow the prompts, and accept the license agreement,
  3. Use Local System to run Splunk under.

Macintosh OSX

  1. Select the .dmg installer for simpler installation,
  2. Follow the prompts to install the application,
  3. At the end of the installation select Start and Show Splunk to start the application and view the user interface in a browser.

 

To start, stop, and administer Splunk

Linux

  1. In a terminal window navigate to the Splunk bin directory
    cd /opt/splunk/bin
  2. To Start Splunk and accept the license agreement during the first start
    ./splunk start --accept-license
  3. The terminal window displays the Splunk web interface address in the The Splunk web interface is at … line. Open a browser to navigate to the address.
  4. To start, stop, and restart the instance, and get help execute
    ./splunk start
    ./splunk stop
    ./splunk restart
    ./splunk help

Macintosh OSX

  1. In a terminal window navigate to the Splunk bin directory
    cd /Applications/Splunk/bin
  2. To start, stop, and restart the instance, and get help execute
    ./splunk start
    ./splunk stop
    ./splunk restart
    ./splunk help

Logging into Splunk the first time

The initial credentials after installation is
Username: admin
Password; changeme

 

Get AWS SSL Certificate resource ids from existing Load Balancers

To launch an Elastic Load Balancer ( ELB ) with an existing SSL certificate using Terraform, you need to specify the AWS certificate resource id. If you have already uploaded the certificate and attached it to an existing load balancer, the following AWS CLI command will display it in the command window. MY_PROFILE is the name of the profile in the square brackets [] in the ~/.aws/credentials file.

aws elb describe-load-balancers --region MY_AWS_REGION --profile MY_PROFILE |grep SSL

To get all information on the load balancers, just omit the grep command:

aws elb describe-load-balancers --region MY_AWS_REGION --profile MY_PROFILE

Create a server image with Packer

Packer is a free, open-source application from Hashicorp. It can generate a server image based on an existing one, and configure it for your special needs. You can use the generated image when you launch a server instance in the cloud or on your local workstation.

Install Packer

Packer script

Packer reads a .json file to generate the new server image.

For Chef in AWS

To allow the Chef Kitchen EC2 driver to read the OS version of the image, include the version in the “Name” as follows:

  • Windows-2012
  • Windows-2012r2
  • Windows-2012r2sp1
  • RHEL-7.2

Generate the server image with Packer

  1. Open a Bash window,
  2. Navigate to the folder of the Packer JSON script,
  3. Execute the following command. Get the AWS access key and secret key from the ~/.aws/credentials file on your Macintosh or Linux workstation. On Windows, the file is at C:\Users\YOUR_USER_NAME\.aws\credentials.
    packer build -var 'aws_access_key=MY_ACCESS_KEY' -var 'aws_secret_key=MY_SECRET_KEY' ./MY_PACKER_SCRIPT.json
  4. The command window will display the ID of the generated image, or you can find it by name in the EC2 section of the AWS console under AMIs.

Share the generated server image with other cloud accounts

If you work in multiple cloud accounts you need to share the generated server image with other accounts

AWS

  1. Log into the AWS account you have used to generate the server image,
  2. On the left side of the EC2 section select AMI and find the new image by name of ID,
  3. On the Permissions tab click the Edit button,
  4. Make sure the Private radio button is selected if you don’t want to share the image publicly,
  5. Enter the account number of the account you want to share the image with,
  6. Check the Add “create volume” permissions… checkbox,
  7. Click the Add Permission button,
  8. When you have added all accounts to share with, click the Save button.

 

Convert PEM files to PPK to use them in PuTTY

When you create a key in AWS you can download it one time in PEM format. To use it in PuTTY, the free SSH and Telnet client, you have to convert it to PPK format.

To install PuTTY, see the Terminal Emulator section in Recommended utilities for your workstation

To convert a PEM file to PPK

  1. Open a terminal window in the folder of the PEM file
  2. Execute the following
    puttygen MYKEY.pem -o MYKEY.ppk

 

Chef Attributes

Chef attributes are global variables that are available for every cookbook on the node. There are multiple formats to declare and use an attribute. For important notes on the syntax, please see Undefined method or attribute error in a Chef recipe.

To override the value of an attribute that is defined in another cookbook, use the following syntax

node.override['ATTRIBUTE_NAME'] = 'NEW_VALUE'

During compilation, this line will replace the default value of the attribute with the NEW_VALUE.

 

Prevent the auto-termination of stranded instances in RighScale

When you launch an instance with RightScale Self Service, and the Chef cookbook execution fails, the instance goes into “stranded” mode. By default RightScale Self Service terminates the stranded instances, so there is no way to remote into them and read log files to find the cause of the problem.

To keep stranded instances running in RightScale

  1. Find the booting instance in Cloud Management and click the instance name,
  2. Click the lock icon on the top of the screen

RightScale Self Service cannot terminate locked instances. To terminate the instance after the troubleshooting process, unlock the instance and terminate the instance by hand.

Error waiting for instance (i-…) to become ready: unexpected state ‘terminated’, wanted target ‘running’

When you launch a server instance with Terraform, sometimes the error message does not contain the underlying cause. When the cloud provider cannot complete the request, many times Terraform displays a generic error message:

Error waiting for instance (i-...) to become ready: unexpected state 'terminated', wanted target 'running'

To find the root cause of the error in AWS

  1. Log into the AWS console and navigate to the EC2 section,
  2. Search for the instance by the instance Id,
  3. You can find the error message at the bottom of the Description tab

In our specific case, it was Client.VolumeLimitExceeded: Volume limit exceeded

We had to increase the volume limit to be able to launch more large EC2 instances.

Upgrade a server on an AWS EC2 instance with minimum risk and downtime

When you need to upgrade an application on an AWS EC2 instance with minimum downtime, there are many options.

Upgrade an EC2 instance

  1. Stop the application, so users don’t make more changes,
  2. Create a backup of the database (snapshot of the RDS instance),
  3. Create a backup of the server (backup image of the EC2 instance),
  4. Upgrade the application on the server,
  5. Start the application,
  6. Test the new version of the application.

In case the upgrade fails, or the post-upgrade test fails

  1. Stop the application,
  2. If you use RightScale to launch servers:
    1. stop the RightLink service on the failed server to prevent RightScale auto terminating the restored server
      (When RightScale finds a new identical server instance, it automatically shuts it down to avoid multiple instances with the same identifier.)
    2. Terminate the failed server
  3. Stop the failed server,
  4. Restore the database from the pre-upgrade backup with a new name,
  5. Restore the server instance from the pre-upgrade backup,
  6. Start the restored server,
  7. Change the database address in the application’s config file to point to the restored database,
  8. Start the application,
  9. Test the restored version of the application.

To make the backup image of the AWS EC2 instance

  1. Open the AWS console and navigate to EC2, Running instances
  2. Find the server instance you want to backup
  3. Right-click the row of the instance and select Image, Create Image

  4. Name the image and click the Create Image button
  5. Save the image Id from the popup

Find the AWS AMI that a RightScale server template is using

When you use RightScale to launch servers in the cloud, you want to use the same base image to test your Chef cookbooks in Test Kitchen.

Packer by Hashicorp is a utility to create custom server images based on cloud images. You supply the image ID and other configuration parameters to create a new custom image.

To find the AMI ID of the base image of the RightScale Server Template

  1. Open the RightScale user interface in your browser,
  2. Select the RightScale account where the server template was created,
  3. In RightScale Cloud Management select  Design / ServerTemplates,
  4. Select the server template,
  5. Select Images,
  6. Select the MultiCloud image,
  7. Select Clouds,
  8. Select the image in the region you are working in,
  9. The Resource UID is the AMI ID of the image.