From b33454ae0b488e79faafef75a06090be6b2ac6a2 Mon Sep 17 00:00:00 2001 From: Arun Isaac Date: Fri, 10 May 2019 16:56:16 +0530 Subject: [PATCH] linux-container: Support container network sharing. * gnu/system/linux-container.scm (container-essential-services): If network is to be shared with the host, remove network configuration files from etc service. (containerized-operating-system): If network is to be shared with the host, remove nscd service and map host's /var/run/nscd if it exists. (container-script): If network is to be shared with the host, do not create network namespace. * guix/scripts/system.scm (system-derivation-for-action): Add #:container-shared-network? argument. (perform-action): Add #:container-shared-network? argument. (show-help): Add "-N, --network" help information. (%options): Add network option. (process-action): Call perform-action with #container-shared-network? argument. * doc/guix.texi (Invoking guix system): Document the "-N, --network" option. Co-authored-by: Christopher Baines --- doc/guix.texi | 5 +++ gnu/system/linux-container.scm | 63 ++++++++++++++++++++++++++++------ guix/scripts/system.scm | 20 +++++++++-- 3 files changed, 75 insertions(+), 13 deletions(-) diff --git a/doc/guix.texi b/doc/guix.texi index 843e909fb2..27e0f72ccb 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -24587,6 +24587,11 @@ When this option is omitted, @command{guix system} computes an estimate of the image size as a function of the size of the system declared in @var{file}. +@item --network +@itemx -N +For the @code{container} action, allow containers to access the host network, +that is, do not create a network namespace. + @item --root=@var{file} @itemx -r @var{file} Make @var{file} a symlink to the result, and register it as a garbage diff --git a/gnu/system/linux-container.scm b/gnu/system/linux-container.scm index ded5f279fe..ce786e39b2 100644 --- a/gnu/system/linux-container.scm +++ b/gnu/system/linux-container.scm @@ -1,6 +1,7 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2015 David Thompson ;;; Copyright © 2016, 2017, 2019 Ludovic Courtès +;;; Copyright © 2019 Arun Isaac ;;; ;;; This file is part of GNU Guix. ;;; @@ -35,7 +36,7 @@ containerized-operating-system container-script)) -(define (container-essential-services os) +(define* (container-essential-services os #:key shared-network?) "Return a list of essential services corresponding to OS, a non-containerized OS. This procedure essentially strips essential services from OS that are needed on the bare metal and not in a container." @@ -51,9 +52,20 @@ from OS that are needed on the bare metal and not in a container." (let ((locale (operating-system-locale-directory os))) (with-monad %store-monad (return `(("locale" ,locale)))))) - base)) + ;; If network is to be shared with the host, remove network + ;; configuration files from etc-service. + (if shared-network? + (modify-services base + (etc-service-type + files => (remove + (match-lambda + ((filename _) + (member filename + (map basename %network-configuration-files)))) + files))) + base))) -(define (containerized-operating-system os mappings) +(define* (containerized-operating-system os mappings #:key shared-network?) "Return an operating system based on OS for use in a Linux container environment. MAPPINGS is a list of to realize in the containerized OS." @@ -76,27 +88,53 @@ containerized OS." (define useless-services ;; Services that make no sense in a container. Those that attempt to ;; access /dev/tty[0-9] in particular cannot work in a container. - (list console-font-service-type - mingetty-service-type - agetty-service-type)) + (append (list console-font-service-type + mingetty-service-type + agetty-service-type) + ;; Remove nscd service if network is shared with the host. + (if shared-network? + (list nscd-service-type) + (list)))) + + (define shared-network-file-mappings + ;; Files to map if network is to be shared with the host + (append %network-file-mappings + (let ((nscd-run-directory "/var/run/nscd")) + (if (file-exists? nscd-run-directory) + (list (file-system-mapping + (source nscd-run-directory) + (target nscd-run-directory))) + (list))))) + + ;; (write shared-network-file-mappings) + ;; (newline) (operating-system (inherit os) (swap-devices '()) ; disable swap - (essential-services (container-essential-services os)) + (essential-services (container-essential-services + os #:shared-network? shared-network?)) (services (remove (lambda (service) (memq (service-kind service) useless-services)) (operating-system-user-services os))) - (file-systems (append (map mapping->fs (cons %store-mapping mappings)) + (file-systems (append (map mapping->fs + (cons %store-mapping + (append mappings + (if shared-network? + shared-network-file-mappings + (list))))) %container-file-systems user-file-systems)))) -(define* (container-script os #:key (mappings '())) +(define* (container-script os #:key (mappings '()) shared-network?) "Return a derivation of a script that runs OS as a Linux container. MAPPINGS is a list of objects that specify the files/directories that will be shared with the host system." - (let* ((os (containerized-operating-system os mappings)) + (let* ((os (containerized-operating-system + os + mappings + #:shared-network? shared-network?)) (file-systems (filter file-system-needed-for-boot? (operating-system-file-systems os))) (specs (map file-system->spec file-systems))) @@ -121,6 +159,9 @@ that will be shared with the host system." ;; users and groups, which is sufficient for most cases. ;; ;; See: http://www.freedesktop.org/software/systemd/man/systemd-nspawn.html#--private-users= - #:host-uids 65536)))) + #:host-uids 65536 + #:namespaces (if #$shared-network? + (delq 'net %namespaces) + %namespaces))))) (gexp->script "run-container" script))) diff --git a/guix/scripts/system.scm b/guix/scripts/system.scm index 3c3d6cbd5f..cf4418f981 100644 --- a/guix/scripts/system.scm +++ b/guix/scripts/system.scm @@ -4,6 +4,7 @@ ;;; Copyright © 2016, 2017, 2018 Chris Marusich ;;; Copyright © 2017 Mathieu Othacehe ;;; Copyright © 2018 Ricardo Wurmus +;;; Copyright © 2019 Christopher Baines ;;; ;;; This file is part of GNU Guix. ;;; @@ -756,13 +757,17 @@ checking this by themselves in their 'check' procedure." (define* (system-derivation-for-action os action #:key image-size file-system-type - full-boot? mappings) + full-boot? container-shared-network? + mappings) "Return as a monadic value the derivation for OS according to ACTION." (case action ((build init reconfigure) (operating-system-derivation os)) ((container) - (container-script os #:mappings mappings)) + (container-script + os + #:mappings mappings + #:shared-network? container-shared-network?)) ((vm-image) (system-qemu-image os #:disk-image-size image-size)) ((vm) @@ -826,6 +831,7 @@ and TARGET arguments." dry-run? derivations-only? use-substitutes? bootloader-target target image-size file-system-type full-boot? + container-shared-network? (mappings '()) (gc-root #f)) "Perform ACTION for OS. INSTALL-BOOTLOADER? specifies whether to install @@ -834,6 +840,8 @@ target root directory; IMAGE-SIZE is the size of the image to be built, for the 'vm-image' and 'disk-image' actions. The root file system is created as a FILE-SYSTEM-TYPE file system. FULL-BOOT? is used for the 'vm' action; it determines whether to boot directly to the kernel or to the bootloader. +CONTAINER-SHARED-NETWORK? determines if the container will use a separate +network namespace. When DERIVATIONS-ONLY? is true, print the derivation file name(s) without building anything. @@ -883,6 +891,7 @@ static checks." #:file-system-type file-system-type #:image-size image-size #:full-boot? full-boot? + #:container-shared-network? container-shared-network? #:mappings mappings)) ;; For 'init' and 'reconfigure', always build BOOTCFG, even if @@ -1020,6 +1029,8 @@ Some ACTIONS support additional ARGS.\n")) (display (G_ " --share=SPEC for 'vm', share host file system according to SPEC")) (display (G_ " + -N, --network for 'container', allow containers to access the network")) + (display (G_ " -r, --root=FILE for 'vm', 'vm-image', 'disk-image', 'container', and 'build', make FILE a symlink to the result, and register it as a garbage collector root")) @@ -1066,6 +1077,9 @@ Some ACTIONS support additional ARGS.\n")) (lambda (opt name arg result) (alist-cons 'image-size (size->number arg) result))) + (option '(#\N "network") #f #f + (lambda (opt name arg result) + (alist-cons 'container-shared-network? #t result))) (option '("no-bootloader" "no-grub") #f #f (lambda (opt name arg result) (alist-cons 'install-bootloader? #f result))) @@ -1182,6 +1196,8 @@ resulting from command-line parsing." #:file-system-type (assoc-ref opts 'file-system-type) #:image-size (assoc-ref opts 'image-size) #:full-boot? (assoc-ref opts 'full-boot?) + #:container-shared-network? + (assoc-ref opts 'container-shared-network?) #:mappings (filter-map (match-lambda (('file-system-mapping . m) m)