HOWTO: Use VPN support with your benchmarks

High-level:

1. Many private clouds (and even public clouds) users will likely not have the benchmark tool on the same L3 network as the cloud they want to benchmark.
2. Some users do have the tool inside the cloud but even then may have different L2 networks configured between tenants even in the same region.
3. Some cloud virtual machines do not have public internet access at all.

How it works:

1. CloudBench has the ability to feed a VPN configuration file through cloud-init and cloud-config via userdata to the virtual machines and bootstrap them onto an OpenVPN-specific L3 network.
2. After cloud-config receives the userdata, it extracts an OpenVPN configuration file and gets all the VMs connected.
3. CloudBench then logs in/rsyncs all of its configuration over the VPN-assigned IP address instead of the public/private IP address assigned by the cloud.
4. After bootstrapping is complete, all intra-workload traffic happens across the normal L3 network within the cloud (not the VPN network). For example, all load generating traffic and application-specific communication that requires higher performance stays within the cloud.

CAVEATS:

1. Cloud-init support is specific to each cloud supported by cloudbench. Currently, this only includes Openstack and DigitalOcean. If it has not been implemented by your driver, then cloudbench cannot function because there are many forms of communication that need to happen between the tool and the cloud, including logging, database management, monitoring, and bootstrapping.

SETUP:

Put the following into your configuration file:

[VM_DEFAULTS]   # You can optionally conditionalize this to your cloud like other paramters
USE_VPN_IP = $True
USERDATA = $True   # Implemented exclusively by each particular cloud driver

[VPN]
SERVER_IP = 159.203.103.89    # public VPN server using the server.conf file from cbtool/configs/generated
SERVER_BOOTSTRAP = 10.9.0.6   # The VPN-assigned IP address of the orchestration server
NETWORK = 10.9.0.0            # User-chosen
SERVER_PORT = 3001            # User-chosen

RUNNING:

1. After you have started up cloudbench, you will get three OpenVPN configuration files automatically generated for you:

• cbtool/configs/XXXXX_server.conf # This one needs to be copied to a publicly-accessible location
• cbtool/configs/XXXXX_client.conf # This one use used by the tool itself.
• cbtool/configs/XXXXX_mongo.conf # Optional: This one allows you to join any more powerful external # mongodb cluster that you may already have available

2. Next, after the tool is started, copy the file cbtool/configs/XXXXX_server.conf to a publicly-accessible server that both VMs in the and the tool can reach. Where it goes is entirely up to you, as every L2/L3 network is different. After you copy it, start openvpn like this:

   openvpn --config XXXXX_server.conf --daemon

• NOTE: A log file is referenced in the configuration file. Refer to it for debugging.

2. After the VPN server is running, make sure that the VPN client is connected to it. If it's not running, feel free to start it manually, as you likely will not have started the VPN server before the tool was started.

   openvpn --config cbtool/configs/generated/XXXXX_client.conf --daemon

• NOTE: A log file is referenced in the configuration file. Refer to it for debugging.
• NOTE: The same goes for the XXXXX_mongo.conf file, should your mongodb cluster be located elsewhere.

3. Finally, the "SERVER_BOOTSRAP" value will likely be wrong, if the client.conf OpenVPN client has not already been started. After you have started it, you need to lookup the VPN-assigned IP address of the tool itself, locally and update the cloudbench configuration with it:

   cbtool$ ifconfig tun0 | grep inet | sed "s/ +/ /g" | grep -oE "[0-9]+.[0-9]+.[0-9]+.[0-9]+" | head -1 10.9.0.6

4. Now, you will need to update the tool with this IP:

   ./cb (MYDIGITALOCEAN) cldalter vpn server_bootstrap 10.9.0.6

• NOTE: You can also do this on the GUI's configuration tab

Now you should be all set. Your benchmarks will now perform all tool <==> cloud communication over the VPN and will keep all intra-workload communication inside the cloud.

Good luck. Join the mailing list if you need help.