Simulating Cisco ACI with ACI Simulator VM

In a nutshell, ACI (Application Centric Infrastructure) is an SDN (Software Define Network) solution from Cisco which allows the network admin to configure and manage the entire network fabric from a single point of management, where all Cisco devices in your infrastructure will be configured and managed from one single GUI through a controller named APIC (Application Policy Infrastructure Controller).

In fact, Cisco ACI is an amazing technology that is worth to learn, but building an ACI lab would be out of reach, as very expensive and not accessible for anyone.

Cisco ACI Simulator to the Rescue

Fortunately, Cisco thought about it and made available an ACI simulator for people interested by this technology to simulator a whole ACI environment. This simulator includes Cisco APIC instances with real production software, as its native tools (GUI & CLI) use the same APIs that are published for third parties, making it possible to simulate any use case. For instance, you would be able to test an ACI VMM integration, by configuring your simulated ACI environment to an existing vCenter installation, and then controlling your vDS switch and port groups from ACI. Furthermore, the Cisco ACI Simulator allows you to simulate faults and alerts to facilitate testing and demonstrate features.

It’s worth noting though, that the ACI Simulator includes simulated switches, so you cannot validate a data path. You can configure the policies but the data plane will not be active.

Installing Cisco ACI Simulator

The ACI simulator comes in two flavors:

  • An .ISO file that can must installed on a Cisco UCS C220 M3 or M4 Rack Server, that you can download here.
  • A .ova file that can be installed VMware Workstations, that you can download here

As I don’t have any Cisco M3/M4 C Seriers available to use for testing, we will use go ahead with the .OVA file deployment as it is easier and faster to deploy. The only difference is that it provides a smaller ACI environment (one Spine, two leafs and one APIC controller) compared the the one deployed with the .ISO file (two Spines, two leafs, three APIC controllers).

Below is the architecture provided by the ACI simulator VM

The ACI Simulator Virtual Machine requirements:

  • 8 vCPU

  • 16GB Memory

  • 80GB Hard Disk Space

You will need a Premium account to download these software and get an activation token to activate them. You may ask one of friends who work for a Cisco partner to get it for you.

The .OVA file is divided into four parts, so you will have to download all four files then aggregate them into one OVA file using the cat command (Linux) or the type command (Windows).

I am using Windows, so the I will use the type command to generate one OVA file

D:\> type acisim-3.1-2m_Part1.ova acisim-3.1-2m_Part.ova acisim-3.1-2m_Part3.ova acisim-3.1-2m_Part4.ova > acisim.ova

This will take a bit of time as each file is approximately 8.5GB of size, so you need to be patient.

Once done, you just need to need to import the resulted OVA in any virtualization software.

I am using VMware Workstation to proceed.

Once the .OVA file is imported, The VM will have two NATted vNIC connected to it. It is OK to change the network as per your configuration. I have configured mine in a Host-Only network named VMnet1.

The subnet range of the VMnet1 network is My machine has an IP of and I will assign to the ACI Simulator VM, so it can be accessible from my PC.

Let’s power on the VM and start the configuration.

After the startup is complete you will be asked to provide an activation key to activate the VM. You will need to have this key to make your VM fully functional.

What is amazing with this simulator is that it gives the same experience as the real environment. You will go through the same steps of configuration of a real ACI APIC controller. You will be prompted to provide the fabric and name ID, the number of controllers in your environment, the POD ID, …etc.

For the sake of simplicity, I will keep most of the inputs with their default values, except the part related to he management network info.

Let’s get started.

No need for IPv6

Choose whether to use a strong password or not.

When all steps are completed, you will be asked to review your configuration and once done, all processes will be started and login prompt will appear.

The simulator should now be accessible through SSH and the Web GUI interface.

Our ACI test environment is fully functional. We have an alert informing us that we have only one controller in our deployment. No worries. It is just a test lab 😉

Cisco ACI Simulator Postpone Configuration

We need now to configure our ACI fabric as we do in real deployment. Here is how it works:

At the startup of first controller, it will detect the leaf that it is connected to and ask us to provide some information about it, like the name and the ID. Once done, the leaf will detect the upstream spine it is connected to and will also ask some info about it. The spine will do the same when it will detect all leaf switches they are connected to it, and so on until all the topology is formed and the controllers have the full picture of the fabric membership.

In our case, we have only one controller, one spine and two leafs. The APIC controller has already detected the spine it is connected to.

Go to Fabric > Inventory > Fabric Membership to check by yourself.

We will use the following topology and will document the needed information accordingly

Double click on the spine node ID and provide the ID and the name, then click on Update.

After sometime, the parent spine will show up and you will need to do the same.

Once all the steps are completed, you will have full test environment to play with.

To have a full overview of your ACI topology, Click on Topology under Fabric > Inventory

Congratulation. You have now your ACI lab environment ready to be used.

I hope you enjoyed reading this article as much as I did while writing it! Cheers 🙂


  1. desusha kiros

    I really appreciate your steps and it is helpful, but it stuck in “Starting APIC1”

    1. Mourad NAKIB (Post author)

      Hi Desusha,
      Make sure you have enough resources assigned to your VM. 16GB for RAM and 8 vCPU. Less than this will not do it.

      1. Alfred

        Hi ,

        me too, stuck in “Starting APIC1” as well. Desusha did you solved it? in my case I have enough resources.

        Version 3.2.1l

        1. Mourad NAKIB (Post author)

          Hi Alfred,

          Are you using SSD disks on your laptop or host server. I followed the same steps with no issue on server with 128GB of RAM having SSD drives.

          Please let us know if your issue is resolved.

        2. jon

          How was this resolved. I also have enough resources.

        3. Prashant

          I have the same problem. Did you find any solution?

      2. Desalegn Kiros Kelele

        Sure I have solved, and thank you so much for your helpful article.

        1. Mourad NAKIB (Post author)

          You’re most welcome!

  2. Kas

    Whenever i start the VM it starts from the beginning from the “setup utility”
    is that normal?

    1. Mourad NAKIB (Post author)

      Yes. Is is. The VM needs to be permanently up! Otherwise, it will loose its configuration and you’ll be prompted to reconfigure it once started again. You can pause the VM instead of powering it off.

  3. Alex

    Hello. When i go to Go to Fabric > Inventory > Fabric Membership
    I do not see anything discovered. So normally, in the real ACI i would see the SN of the first leaf, and it seems to be the same in your instruction. However in my case i do not see anything.
    How long did you wait for the first leaf to appear?

    1. Mourad NAKIB (Post author)

      Hi Alex,
      I had some similar issues with some other ACI simulator versions. The ACI simulator is just for testing purpose and not supported by Cisco. You can try to use the same version I’m using in this article (3.1-2m) and see if it works.

      1. Bob

        The same issue here. Version: 3.2(1m) and nothing under: Fabric > Inventory > Fabric Membership. Any suggestion?

        1. Ankit Thakrar

          You need to go under unregistered node. You will see a leaf which you need to register. Once you register it will discover another Leaf and Spine which requires to be register.

        2. Vojtech

          Hi I had same issue.

          Just reload the ACI-SIM VM, keep default configurations except the out-of-band management information (IP, Default-GW).
          And i was able to discovery the first LEAF.

  4. Shafqat

    Hi Everyone ,

    is there any way we can connect any Virtual device to the leaf using this ACI simulator .

    if build any lab how to test connectivity on this simulator like any OSPF ,BGP etc

    please advise if there is a way or any website link where i can test the connectivity etc

    1. Sharif Khan

      Hello Shafqat,

      Have you got any solution to connect the other device to run OSPF, BGP?

      I am also facing the same issue.

      Sharif Khan

      1. Mourad NAKIB (Post author)

        Hi Sharif,

        No. You cannot. This is just a simulator.

  5. Prashant

    Hi, my VM is stuck on “Starting APIC1”. Any solution? I have enough resources.

  6. Prashant

    Hi My ACI is Activated but stuck at “APIC1 STARTING”. Any Solution

    1. Ali

      Just reboot the VM and you should be okay.

  7. Simsima

    Hi all!

    is there any way to access via SSH to the leaves, I’m able to access to apic via ssh but not the leaves, as you know it’s a simulator and the TEP address shall be the default address.

    thanks in advance.

    1. Steve

      Hi Simsima
      You can get on to the leaf switches, but not much point as there is no command structure. If you:
      1, SSH to the APIC
      2, Drop in to the bash shell
      3, attach Leaf101
      1, SSH to the APIC
      2, SSH to the leaf TEP address

      Either way you can’t run any commands as it doesn’t seem to be supported in the simulator.

  8. Shiv

    Hi I am able to ping gateway but not able to ping ACI IP and even GUI also not working.

    1. Jignesh

      I have same issue ping work to oob IP , can ssh as well but authentication failure and web GUI not loading

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