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IBM App Connect now allows different sizes of integration servers

By Karen Broughton-Mabbitt posted Tue August 25, 2020 06:43 AM

Author - John Reeve

The App Connect enterprise capability on IBM Cloud has allowed users to upload and run BAR files, authored using the on-premises toolkit, for many years now. A BAR file is run by a single integration server being created that has 0.5 Virtual Processor Core (VPC) of capacity with 4 GBytes of memory. These are relatively large integration servers that have sufficient processing power to handle a large number of integrations. In the past, this sizing has led some users to need to group together several logically separate message flows into a single BAR file, in order to get maximum value for money.

App Connect on IBM Cloud now supports the use of smaller integration servers so that the total capacity bought can be spread between many smaller BAR files. This lets you run many more separate BAR files, which allows for finer-grained control of updating, starting, and stopping running integrations independently.

In addition to allowing different sized integration servers, it is also possible to define the number of replicas of an integration server required to allow for better availability of the integrations. All replicas for an integration server share the same HTTP hostname, and HTTP traffic is spread between the integration servers. If one server happens to crash or get restarted for any reason then the other servers continue unaffected. When a system update happens to App Connect, only one of the replicas is restarted at a time so the others can continue to handle requests.

The new Import a BAR file screen looks like the following image:

where this allows you to select the size and number of replicas for the integration server. It also displays the quantity of VPCs that are required to run the integration based on the values selected. Selecting a high number of replicas and memory will result in a higher VPC cost, but selecting smaller values allows for a better spread of VPC cost between running BAR files. An error will be displayed when you start an integration if you exceed the total allowed VPCs for your account. On the Lite plan, the limit is 1.25 VPCs.

It is also possible to change the values for memory and number of replicas after a BAR file has been imported, by editing the integration details as shown in the following image:

When running with additional replicas some functions will not work as you might first expect, due to the fact that completely separate integration servers will be created. For example, collecting service trace or trying to use the graphical debugger from an on-premises Toolkit will only work correctly when running with a single replica. When using event driven nodes, like Aggregation or collector, then the state store will not be shared between replicas and this should be taken into account when deciding to use additional replicas.