Wednesday, June 5, 2019

Containerize legacy applications (Epicor E4SE) - take 3

After I figured out the MSDTC issue, all seemed well until I got hit by the MSMQ problem, even though I have diverted the queue to be on a remote machine, E4SE refused to work until it is satisfied that MSMQ is installed on the container, it turned out that MSMQ support in Container is only possible after build 1803 which isn't supported under Windows Server 2016.

Since I havne't got a 2019 server box on hand, I opted to use my windows 10 machine and pulled the 1803 image and rebuilt everything, good news is after all these the MSMQ issue is also gone.
will do more testing later but hopefully there should be no more major issues.

Tuesday, June 4, 2019

Containerize legacy applications (Epicor E4SE) - take 2

In my previous post, I almost thought everything is working fine until I got hit by this infamous MSDTC problem, I came across a few posts online and although they are quite inspiring and some of them have got it working, they are not quite the same situation as I got.

here is a summary of what people have got working for MSDTC:
> both app and sql are containerised
> under AWS, using ELB and port mapping
> under Azure, using CNI 

what I want to achieve:

> Containerized web app
> SQL Server running on VM
>  the web app will need to enable windows authentication under the domain, sql server is running under domain also

For me, my window server 2016 container host is running under vmware, initially I want to use the transparent network to make things easier however enabling promiscuous mode on the vmware environment doesn't seem to be an option so  this is out, at the end I ended up with running container just in NAT network and expose custom port to host.

It turns out that the above mentioned AWS scenario is the closest to mine, what I ended up with is to use KEMP load balancer in the place of ELB, 

what is really important:

> fix MSDTC port on the container and expose to host.
> expose RPC port 135 to host using customer port number
> expose port 80 to host via custom port number.

the KEMP load balancer will then map the ordinary port number to the custom port number on the container host, we also need to create the hostname DNS to point to the KEMP load balancer IP.

the above scenario only involves one container instance, if we need run multiple replica then we will most likely need to multiple the setup but I assume it is all straight forward and no drama here.

and finally MSDTC is working fine and hopefully the PoC is a success

Sunday, June 2, 2019

Machine learning

These days machine learning is an inescapable part of the realm if you are working in data field, as such I think it is necessary to learn something new and refresh what was taught at school over  a decade ago ... I took the coursea course "machine learning" by andrew ng  and finished the course today. I would recommend it to anyone who has interest to get to know a bit of machine learning , this course fall bit short on the theory and mathematics involved thought but that is understandable being an intro course.