troubleshooing missing ip in k8s ( metallb-system)
some ip within metallb-system suddently does not work arp -a arping ip_address iptables -L -n ip route get 192.168.1.88 sudo ip neigh flush all kubectl -n metallb-system rollout restart deployment…
video streaming HLS, DASH
What is DASH and HLS? DASH (Dynamic Adaptive Streaming over HTTP) and HLS (HTTP Live Streaming) are both popular streaming protocols used to deliver multimedia content over the internet, but…
postfix transport_maps ( routing based on destination domain )
Background/Use case sometimes we need want to based on the destimation/domain to use different STMP server ( instead of relying on automatically search mx record) the transport_maps is a good…
debian 12 install boot from usb stick
New install: Download any .iso file from: ( for debian 12) https://www.debian.org/releases/bookworm/debian-installer/ Cp to usb stick https://www.debian.org/releases/bookworm/amd64/ch04s03.en.html # cp debian.iso /dev/sdX # sync Insert usb to PC to boot…
screen tmux cheat sheet
Screen screen -d -R your_session name //split only the monitor screen ctrl-a ( release the kb ), then press: | for vsplit —> need this step : ctrl-a, c…
sip monitoring tools
Some good monitoring tools: homer: easy to install with docker for its server and install helifpy on a sip/client/host : nohup ./heplify -hs homer_server:9060 & grep sngrep, ngrep pcap tcpdump/wireshark…
Kubernetes Quick Start
Learning curve for Kubernetes (K8s) could be steep. For most users who are already familiar with basic networking, OS/Linux, docker container technologies etc, the difficulties , I personally think, is…
gdb and signal handling ( especially sigwaitinfo )
How gdb generally works In a debugging session, when the debugger wants to set a breakpoint, it replaces an instruction by int3 When the trap instruction (0xCC on x86) is executed,…
srtp and h.235.6 secure rtp
SRTP RFCs and h.235 is Not an easy read. Here is my very high level beriefing: AES Encryption (1) AES is the foundation for both srtp and h.235.6 secured rtp…
openstack
I spent several days to install openstack on debian 8 at one testing box with two NICs. Finally got a basic working system! It has with a controller node running neutron,…
