Cannot establish client and server connection for Web Serving benchmark inside QEMU-KVM about cloudsuite HOT 3 CLOSED

Hi Arnab:
This is an advanced use case that will require some more thinking on our end, since there are 2 levels of virtualization involved now (QEMU/KVM and docker running inside the VMs). Just a few additional questions for you:

• Are you running all of these containers on the same VM?
• What is your DHCP setup? I am assuming that you are running the DHCP daemon on the host server and it is assigning your VMs IPs?
• Which QEMU networking frontend are you using?
• Using host network inside the VM means that all of the traffic from the containers should pass through the emulated I/O interface exposed by QEMU. However, if the docker stack is not working harmoniously with that emulated interface, it can cause problems.

A 502 error is likely meaning that the networking setup is the issue, as it signals that the entire HTTP request was not successfully completed.

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Hi Mark,
Thank you for your reply.

• I use the same VM to run all of the Docker images (webserver, client, memcache, mysql_server).
• No the guest OS inside the VM will set up a virtual DHCP server that will assign IPs to the VM. The VMs will be assigned IPs starting from 10.0.2.15.
• I use the user-mode networking feature inside of QEMU. This will allow the guest VMs access to the internet but the ICMP protocol will not work inside of the VM (normal TCP/UDP works fine). This could be a helpful link to know - ( https://en.wikibooks.org/wiki/QEMU/Networking ) if you are unaware.
• The fact that we use --net=host when we run the docker images imposes the host network for the Docker containers. And yes, it could be that a different networking setup will be needed.

Note:
We tried investigating into more details about the issue and when we tried looking into the nginx server logs - we got repeated messages like this
child #n terminated because of SIGBUS errors: core dumped (where n > 1)

Regards,
Arnab

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I'm closing this for now.
Feel free to reopen it if you have any further questions.

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