Linux

GoogleWiFi + Pi-hole and NordVPN

GoogleWiFi + Pi-hole and NordVPN

Hello friends, as I promised in my previous post I’m going to tell you about configuring GoogleWiFi router with a Raspberry Pi server acting as DHCP and DNS server / VPN gateway. While part related to NordVPN is vendor specific I feel it would not be too hard to use similar setup with any VPN provider. Feel free to skip VPN related part.

I’m not sponsored by NordVPN, instructions provided as is and as any information from the Internet should be used carefully.

Debugging DHCP using tcpdump

Debugging DHCP using tcpdump

With lot of time spent home during stay-at-home order active in my area I decided it’s a time to overhaul my home network setup.

I think I’ll get into details in the following posts but at this time I want to tell about an issue with DHCP leases I was able to track down using tcpdump.

Moved to Hugo

Moved to Hugo

Hey-hey kids it has been a while, right? Ok, I’m planning to blow the dust off this blog.

Don’t expect anything grandiose yet but I did some homework and moved the blog from Octopress to Hugo so this tin lizzy has a heart of a fighter jet now.

See you soon.

Ubuntu user hits thread number limit preventing SSH login

Ubuntu user hits thread number limit preventing SSH login

Recently I was investigating quite an interesting issue - there is Ubuntu based VM our testers run some tests on. It was reported they’re unable to log into the virtual machine.

After a brief investigation it became clear the issue is not network or SSH key related.

These are records from auth log:

/var/log/auth.log

Feb 28 20:21:39 test-instance sshd[21954]: pam_unix(sshd:session): session opened for user ubuntu by (uid=0)
Feb 28 20:21:39 test-instance systemd-logind[756]: New session 75 of user ubuntu.
Feb 28 20:21:39 test-instance sshd[21954]: fatal: fork of unprivileged child failed
Feb 28 20:21:39 test-instance systemd-logind[756]: Removed session 75.

Quite an obscure error message, but smells like cgroup problem. Indeed:

GCE and self hosted k8s 1.6 no route created

GCE and self hosted k8s 1.6 no route created

There is an annoying bug in Kubernetes 1.6 running on GCE with Calico/Flannel networking operating via CNI plugin interface.

You may experience same issue if kubelet on your nodes runs with options

--network-plugin=cni --cloud-provider=gce

When a new node is added to the k8s cluster it’s recognized as ‘Ready’ but no pods except Calico/Flannel pod are being scheduled there.