Previous part is here. This post will explain, how to restart your web site at specific intervals without returning errors to clients. You can scroll to solution, if you are no interested in my thoughts and to see what I try.

Thoughts and research

As I mentioned in this post, I decided to restart my web site periodically to avoid out of memory issue. And I would like to mention that it wasn’t easy to do. Obviously, restarting web site is super simple and all you need is to restart its service. But that means that your web site will be unavailable for some time. Depending on size of the web site, we are talking about seconds or

Some time ago, I wrote series of posts on how to run .NET Core app on AWS Lightsail Linux instance. Everything worked nice but sometimes, about once per month my web site stopped responding. And I cannot connect to my instance at all to diagnose that issue. All I can do is just restart my AWS instance. At the beginning I thought it could be AWS issue, or perhaps some issues in .NET. I updated everything I can, but problem persists. And when it happened last time, I decided to check kernel logs and I found this:

Feb 10 07:31:18 ip-1-2-3-4 kernel: [1512878.216567] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/system.slice/,task=dotnet,pid=511,uid=1001
Feb 10 07:31:18 ip-1-2-3-4 kernel: [1512878.216597] Out of memory: Killed process 511 (dotnet) total-vm:3007440kB, anon-rss:105260kB, file-rss:0kB, shmem-rss:0kB, UID:1001 pgtables:712kB oom_score_adj:0
Feb 10 07:31:18 ip-1-2-3-4 kernel: [1512878.241642] oom_reaper: reaped process 511 (dotnet), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB

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  • .NET

Recently I was asked to check why one of our applications crashes when it calls CreateNamedPipe function. Everything works fine in the x64 version, but the x86 version crashes. There are no differences in the code between x86 and x64 and they compiled the same.

Let’s see how CreateNamedPipe defined in our code:

[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
static extern SafePipeHandle CreateNamedPipe(string lpName, uint dwOpenMode,
    uint dwPipeMode, uint nMaxInstances, uint nOutBufferSize, uint nInBufferSize,
    uint nDefaultTimeOut, SECURITY_ATTRIBUTES securityAttributes);

and here is how it called:

SafePipeHandle safeHandle = CreateNamedPipe(
                cPipeAccessDuplex |
                cPipeTypeMessage |
                nOutBufferSize: 0,
                nInBufferSize: 0,

Everything looks correct. I checked flags, compared them with