mdebray/tvl-depot
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Add systemd basics & unit types

Browse source
This commit is contained in:
Vincent Ambo 2016-01-21 12:46:26 +01:00
parent f15a12bc4e
commit ed1184b326
No known key found for this signature in database
GPG key ID: 66F505681DB8F43B
2 changed files with 58 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
slides.pdfpc
View file

@ -34,3 +34,21 @@ Lennart Poettering of Pulseaudio fame and Kay Sievers decided to implement a new
### 7 ### 7
Systemd's design goals Systemd's design goals
### 8 ### 8
No more init scripts with opaque effects -> services are clearly defined units
Unit dependencies -> systemd can figure out what can be started in parallel
Process supervision: Unit can be configured in many ways, e.g. always restart, only restart on success etc
Service logs: We'll talk more about this later
### 9
Units are the core component of systemd that users deal with. They define services and everything else that systemd needs to start and manage.
Note that all these are the names of the respective man page on a system with systemd installed
Types:
systemd.service - processes controlled by systemd
systemd.target - equivalent to "runlevels", grouping of units for synchronisation
systemd.timer - more powerful replacement of cron that starts other units
systemd.path - systemd equvialent of inotify, watches files/folders -> launches units
systemd.socket - expose local IPC or network sockets, launch units on connections
systemd.device - trigger units when certain devices are connected
systemd.mount - systemd equivalent of fstab entries
systemd.swap - like mount
systemd.slice - unit groups for resource management purposes
... and a few more specialised ones

40
slides.tex
View file

@ -1,6 +1,8 @@
\documentclass[14pt]{beamer} \documentclass[14pt]{beamer}
\usetheme{metropolis} \usetheme{metropolis}
\newenvironment{code}{\ttfamily}{\par}
\title{systemd} \title{systemd}
\subtitle{The standard Linux init system} \subtitle{The standard Linux init system}
@ -50,6 +52,44 @@
\end{itemize} \end{itemize}
\end{frame} \end{frame}
\begin{frame}{Systemd - the basics}
\begin{itemize}
\item No scripts are executed, only declarative units
\item Units have explicit dependencies
\item Processes are supervised
\item cgroups are utilised to apply resource limits
\item Service logs are managed and centrally queryable
\item Much more!
\end{itemize}
\end{frame}
\begin{frame}{Systemd units}
Units specify how and what to start. Several types exist:
\begin{code}
\small
\begin{columns}[T,onlytextwidth]
\column{0.5\textwidth}
\begin{itemize}
\item systemd.service
\item systemd.target
\item systemd.timer
\item systemd.path
\item systemd.socket
\end{itemize}
\column{0.5\textwidth}
\begin{itemize}
\item systemd.device
\item systemd.mount
\item systemd.swap
\item systemd.slice
\end{itemize}
\end{columns}
\end{code}
\end{frame}
\begin{frame}{}
\end{frame}
\section{Demo} \section{Demo}
\section{Controversies} \section{Controversies}