Glimpse on Systemd: A Modern Service Manager for Linux


  • Systemd is a system and service manager for Linux operating systems. It is designed to be backwards compatible with SysV init scripts, and provides a number of features such as parallel startup of system services at boot time, on-demand activation of daemons, support for system state snapshots, or dependency-based service control logic. It may refer to all the packages, utilities and libraries around daemon.
  • Systemd was designed to overcome the shortcomings of init and itself is a background processes which is designed to start processes in parallel, thus reducing the boot time and computational overhead. It has a lot other features as compared to init.
Why there was a need to replace init?
  • A init process starts serially i.e., one task starts only after the last task startup was successful and it was loaded in the memory. This often resulted into delayed and long booting time. However, systemd was not designed for speed but for getting the things done neatly which in turns avoid all the UN-necessary delay.

Systemd_cheatsheet:




Thanks to tecmint for made such a clarity post on init and systemd concepts.

Comments

Post a Comment

Popular posts from this blog

Resolved: DOCKER: Error response from daemon: Could not attach to network / rpc error: code = 7 desc = network not manually attachable.

Image
I got this error: 'docker: Error response from daemon: Could not attach to network <nw-name>: rpc error: code = 7 desc = network <nw-name> not manually attachable.' when i try to create the container on the overlay network on swarm mode enabled, In docker 1.12 with swarm mode enabled, "Swarm" scoped networks (see the "SCOPE" column) cannot be used for docker run, only for services and now it has been rectified. I'm using updated version of docker, but still why i'm experiencing the error ? because the network just created but not manually attachable. To fix the issue we gonna use --attachable flag while creating network. [ --attachable             Enable manual container attachment ] (Need to create service on the overlay network, so that the overlay network will available / list on the worker node) docker inspect attnw (attnw is our test network)should show your own c
Read more

yum failed 6 times. Cannot continue!

Error while cPanel installation: (ERROR): - ssystem [EXIT_CODE] '/usr/bin/yum' exited with 1 (ignored) (DEBUG): - ssystem [END] (FATAL): yum failed 6 times. Cannot continue! fix: It looks like you have some name resolution issues on the server. Just run the following commands on your server and it will resolve the name resolution issues. #echo "nameserver 8.8.8.8" >> /etc/resolv.conf #echo "nameserver 8.8.4.4" >> /etc/resolv.conf if it is not working properly still facing same error, then here we go, # rpm -e --nodeps bind-chroot # rpm -e --nodeps bind # yum install bind
Read more

unexpectedly shrunk window (repaired) in dmesg log - TCP Peer

Don't Panic, This normally occurs when a client decides to reduce its TCP window size, without the server expecting it. This can be the case when fragmentation is an issue, or when the client is using an embedded device with very little NIC buffer memory. This is a completely normal behaviour, and you’re likely to see quite a few such packets in your log. The messages are informational only, and are used to debug networking issues. I’d be worried if you saw hundreds of thousands of these packets, since there are attacks that involve packet fragmentation and small window sizes, but otherwise it’s just the normal sort of noise you should expect to see on any internet-facing network. In fact, the “repaired” part of your message is showing that your network driver fixed the issue, which is usually done by concatenating the payloads of two fragmented packets together. Shouldn’t be an issue at all. … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … … 
Read more