Lab 1.6: Build a Basic LTM Config using REST Transactions

In this lab, we will build a basic LTM Config using iControlRest Transactions.

Task 1 - Create a Transaction

Transactions are beneficial in cases where you would like to have discrete REST operations to act as a batch operation. As a result, the nature of a transaction is that either all the operations succeed or none of them do (all-or-nothing). This is very useful when we are creating a configuration that is linked together because it allows the rollback of operations in case one fails. All the commands issued are queued one after the other in the Transaction. We will also review how to change the order of a queued command or remove a single command from the queued list before committing.

Note

Transactions are essential to ensure that an Imperative process is Atomic in nature.

Warning

Transactions have a default timeout of 120 seconds. Taking longer than the timeout period to execute a transaction will result in the automatic deletion of the Transaction. To avoid having to redo the steps in this task, please first read through the steps below and execute each of them promptly.

Perform the following steps to complete this task:

1. Expand the Lab 1.6 - Build a Basic LTM Config using Transactions folder in the Postman collection:

   

2. Click the Step 1: Create a Transaction request. Examine the URL and JSON Body. We will send a POST to the /mgmt/tm/transaction endpoint with an empty JSON body to create a new transaction.

   

3. Click the Send button to send the request. Examine the response and find the transId attribute. Additionally, notice that there are timeouts for both the submission of the Transaction and how long it would take to execute. Please be aware that upon exceeding the timeoutSeconds period, the transId will be silently removed:

   

   The transId value has been automatically populated for you in the bigip_transaction_id environment variable:

   

4. Click the Step 2: Add to Transaction: Create a HTTP Monitor request in the folder. This request is similar to a non-transaction enabled request in terms of the POST request method, URI, and JSON body. The difference is that a header named X-F5-REST-Coordination-Id with the value of the transId attribute is added to the Transaction:

   

5. Click the Send button and examine the response.

6. Examine and click Send on Steps 3-6 in the folder.

7. Click Step 7: View the Transaction Queue. Examine the request type and URI and click Send. This request allows you to see the current list of ordered commands in the Transaction.

Task 2 - Modify a Transaction

1. Click the Step 8: View Queued Command 4 from Transaction request in the folder. Examine the request method and URI. We will GET command number 4 from the transaction queue.

   

2. Click the Step 9: Change Eval Order 4 -> 1 request in the folder. Examine the request method, URI, JSON body, then click Send. We will PATCH our transaction resource and change the value of the evalOrder attribute from 4 to 1 to move to the first position of the transaction queue:

   

   Note

   Requests in the ordered transaction queue must obey the order of operations present in the underlying BIG-IP system.

   Warning

   When sending the Header X-F5-REST-Coordination-Id, the system assumes that you want to ADD an entry in the transaction queue. You MUST remove this header if you want to issue any other transaction queue changes (such as deleting an entry from the queue, changing the order, or committing a transaction). If you fail to remove the header, the system will respond with a 400 HTTP error code with the following error text:

   "message": "Transaction XXXXX operation .... is not allowed to be added to Transaction."

3. Click the Step 10: View the Transaction Queue Changes request in the folder. Verify that command number 4 has moved into position 1 and the order of all other commands has been updated accordingly.

Task 3 - Commit a Transaction

1. Click the Step 11: Commit the Transaction request in the folder. Examine the request type, URI, and JSON body. We will PATCH our transaction resource and change the value of the state attribute to submit the Transaction:

   

2. Click the Send button and examine the response. The state may already be COMPLETED. However, it is a good practice to explicitly check for this.

3. Click the Step 12: View the Transaction Status request in the folder and click the Send button. Verify that the state of the Transaction is COMPLETED.

4. You can verify the configuration was created on the BIG-IP device via the BIG-IP A GUI bookmark or at https://10.1.1.7.

5. Verify that the virtual server works by opening http://10.1.10.120 or using the Module 1 VIP01 bookmark in Chrome web browser