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1 DNF 概述
Linux 6 和7 是一个跨度有点大的2个linux 版本，主要体现在一些管理工具和命令上。 所以如果要想用好Linux 7+以上版本的Linux，就必须学习这些新的管理方式和命令。
在之前的博客中，我们已经了解到了Linux 7中的网络管理工具：nmcli，如下：
Linux 7 中网络配置管理（nmcli工具） 说明
https://www.cndba.cn/cndba/dave/article/151
在本片博客中，我们将介绍Linux 8中的包管理工具：DNF。
关于dnf, 有一篇英文的介绍，链接如下，可以参考：
简单的来说，DNF(Dandified Yum)是新一代的RPM软件包管理器。 DNF包管理器克服了YUM包管理器的一些瓶颈，提升了包括用户体验，内存占用，依赖分析，运行速度等多方面的内容。
从Linux 8开始，Linux 已经将默认的包管理工具替换成了DNF，而不是以前版本中的YUM。
Linux yum 命令介绍
https://www.cndba.cn/Dave/article/709
在RHEL或CentOS7系统中默认没有安装DNF，但可以在使用YUM的同时使用DNF。
安装epel-release依赖：yum install epel-release
安装DNF包：yum install dnf 或者 yum install dnf -y
dnf命令说明：
[root@www.cndba.cn ~]# cat /etc/redhat-release
Red Hat Enterprise Linux release 8.3 Beta (Ootpa)
[root@www.cndba.cn ~]#
[root@www.cndba.cn ~]# uname -a
Linux Dave 4.18.0-221.el8.x86_64 #1 SMP Thu Jun 25 20:58:19 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
[root@www.cndba.cn ~]# man dnf
DNF(8) DNF DNF(8)
NAME
dnf - DNF Command Reference
SYNOPSIS
dnf [options] <command> [<args>...]
DESCRIPTION
DNF is the next upcoming major version of YUM, a package manager for RPM-based Linux distributions. It roughly maintains CLI compatibility with YUM and defines a strict API for extensions and plugins.
Plugins can modify or extend features of DNF or provide additional CLI commands on top of those mentioned below. If you know the name of such a command (including commands mentioned below), you may find/install the package which provides it using the appropriate virtual provide in the form of dnf-command(<alias>), where <alias> is the name of the command; e.g.``dnf install 'dnf-command(versionlock)'`` installs a versionlock plugin. This approach also applies to specifying dependencies of packages that require a particular DNF command.
Return values:
· 0 : Operation was successful.
· 1 : An error occurred, which was handled by dnf.
· 3 : An unknown unhandled error occurred during operation.
· 100: See check-update
· 200: There was a problem with acquiring or releasing of locks.
Available commands:
· alias
· autoremove
……
2 DNF 全局配置文件
DNF 默认使用的全局配置文件是/etc/dnf/dnf.conf， 所有*.repo 源文件都在/etc/yum.repos.d 目录下。 并且源文件里配置的优先级要高于全局配置文件，dnf.conf。
[root@www.cndba.cn ~]# cd /etc/dnf
[root@www.cndba.cn dnf]# ls
aliases.d dnf.conf modules.d modules.defaults.d plugins protected.d vars
[root@www.cndba.cn dnf]# cat dnf.conf
[main]
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=True
best=True
skip_if_unavailable=False
[root@www.cndba.cn dnf]# man dnf.conf
DNF.CONF(5) DNF DNF.CONF(5)
NAME
dnf.conf - DNF Configuration Reference
DESCRIPTION
DNF by default uses the global configuration file at /etc/dnf/dnf.conf and all *.repo files found under
/etc/yum.repos.d. The latter is typically used for repository configuration and takes precedence over global
configuration.
The configuration file has INI format consisting of section declaration and name=value options below each on
separate line. There are two types of sections in the configuration files: main and repository. Main section
defines all global configuration options and should be only one.
The repository sections define the configuration for each (remote or local) repository. The section name of
the repository in brackets serve as repo ID reference and should be unique across configuration files. The
allowed characters of repo ID string are lower and upper case alphabetic letters, digits, -, _, . and :. The
minimal repository configuration file should aside from repo ID consists of baseurl, metalink or mirrorlist
option definition.
DISTRIBUTION-SPECIFIC CONFIGURATION
Configuration options, namely best and skip_if_unavailable, can be set in the DNF configuration file by your
distribution to override the DNF defaults.
[MAIN] OPTIONS
arch string
The architecture used for installing packages. By default this is auto-detected. Often used together
with ignorearch option.
……
3 DNF 源配置文件
从我们使用角度来说，最主要的就是配置DNF的源文件。
在RHEL8中把软件源分成了两部分，BaseOS 和AppStream。
- BaseOS 存储库：BaseOS 存储库以传统 RPM 包的形式提供底层核心 OS 内容。
- AppStream 存储库：Application Stream 存储库提供用户可能希望在给定用户空间中运行的所有应用程序。
在使用本地ISO镜像做源时，针对这2种类型的源，需要分别进行配置。
Linux 8 之前的yum源配置可以参考我之前的博客：
Linux 平台下 yum 源 配置 手册
https://www.cndba.cn/dave/article/154
3.1 Linux 8 中使用在线源
在服务器能联网的情况下，可以直接使用在线的dnf源。
下载dnf源：
[root@www.cndba.cn yum.repos.d]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repo
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 2595 100 2595 0 0 25441 0 --:--:-- --:--:-- --:--:-- 25441
查看dnf 源：
[root@www.cndba.cn dnf]# dnf repolist
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
repo id repo name
AppStream CentOS-8 - AppStream - mirrors.aliyun.com
base CentOS-8 - Base - mirrors.aliyun.com
extras CentOS-8 - Extras - mirrors.aliyun.com
[root@www.cndba.cn dnf]#
这里显示了3个repo 源。
查看源文件的具体内容：
[root@www.cndba.cn yum.repos.d]# ls
CentOS-Base.repo redhat.repo
[root@www.cndba.cn yum.repos.d]# cat CentOS-Base.repo
# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client. You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#
[base]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/BaseOS/$basearch/os/
http://mirrors.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/BaseOS/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/extras/$basearch/os/
http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/extras/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/os/
http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/centosplus/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[PowerTools]
name=CentOS-$releasever - PowerTools - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/PowerTools/$basearch/os/
http://mirrors.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/PowerTools/$basearch/os/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[AppStream]
name=CentOS-$releasever - AppStream - mirrors.aliyun.com
failovermethod=priority
baseurl=https://mirrors.aliyun.com/centos/$releasever/AppStream/$basearch/os/
http://mirrors.aliyuncs.com/centos/$releasever/AppStream/$basearch/os/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/AppStream/$basearch/os/
gpgcheck=1
gpgkey=https://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-Official
[root@www.cndba.cn yum.repos.d]#
3.2 使用本地DNF源
如果服务器不能联网，那么可以直接使用ISO 镜像做源。
将ISO 文件挂载到系统：
[root@www.cndba.cn dnf]# mount /dev/cdrom /mnt
mount: /mnt: WARNING: device write-protected, mounted read-only.
[root@www.cndba.cn dnf]# ls /mnt
AppStream EFI extra_files.json images media.repo RPM-GPG-KEY-redhat-release
BaseOS EULA GPL isolinux RPM-GPG-KEY-redhat-beta TRANS.TBL
[root@www.cndba.cn dnf]#
创建源文件：dave.repo
[root@www.cndba.cn yum.repos.d]# cat /etc/yum.repos.d/dave.repo
[dave-AppStream]
name=AppStream
baseurl=file:///mnt/AppStream
gpgcheck=0
enabled=1
[dave-BaseOS]
name=BaseOS
baseurl=file:///mnt/BaseOS
gpgcheck=0
enabled=1
[root@www.cndba.cn yum.repos.d]#
清空并重建cache:
[root@www.cndba.cn yum.repos.d]# dnf clean all
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
18 files removed
[root@www.cndba.cn yum.repos.d]# dnf makecache
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
CentOS-8 - Base - mirrors.aliyun.com 4.3 MB/s | 2.2 MB 00:00
CentOS-8 - Extras - mirrors.aliyun.com 25 kB/s | 8.1 kB 00:00
CentOS-8 - AppStream - mirrors.aliyun.com 10 MB/s | 5.8 MB 00:00
AppStream 296 MB/s | 6.3 MB 00:00
BaseOS 159 MB/s | 2.3 MB 00:00
Metadata cache created.
[root@www.cndba.cn yum.repos.d]#
与linux 8之前的yum 源配置基本参数都是一样的，唯一的区别就是要分别配置好BaseOS和AppStream。
4 DNF 命令
dnf 的命令与yum 基本都是兼容的，所以这里不再具体命令，直接将dnf的命令帮助列举如下：
[root@www.cndba.cn ~]# dnf -v
Loaded plugins: builddep, changelog, config-manager, copr, debug, debuginfo-install, download, generate_completion_cache, needs-restarting, playground, product-id, repoclosure, repodiff, repograph, repomanage, reposync, subscription-manager, uploadprofile
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
usage: dnf [options] COMMAND
List of Main Commands:
alias List or create command aliases
autoremove remove all unneeded packages that were originally installed as dependencies
check check for problems in the packagedb
check-update check for available package upgrades
clean remove cached data
deplist List package's dependencies and what packages provide them
distro-sync synchronize installed packages to the latest available versions
downgrade Downgrade a package
group display, or use, the groups information
help display a helpful usage message
history display, or use, the transaction history
info display details about a package or group of packages
install install a package or packages on your system
list list a package or groups of packages
makecache generate the metadata cache
mark mark or unmark installed packages as installed by user.
module Interact with Modules.
provides find what package provides the given value
reinstall reinstall a package
remove remove a package or packages from your system
repolist display the configured software repositories
repoquery search for packages matching keyword
repository-packages run commands on top of all packages in given repository
search search package details for the given string
shell run an interactive DNF shell
swap run an interactive DNF mod for remove and install one spec
updateinfo display advisories about packages
upgrade upgrade a package or packages on your system
upgrade-minimal upgrade, but only 'newest' package match which fixes a problem that affects your system
List of Plugin Commands:
builddep Install build dependencies for package or spec file
changelog Show changelog data of packages
config-manager manage dnf configuration options and repositories
copr Interact with Copr repositories.
debug-dump dump information about installed rpm packages to file
debug-restore restore packages recorded in debug-dump file
debuginfo-install install debuginfo packages
download Download package to current directory
needs-restarting determine updated binaries that need restarting
playground Interact with Playground repository.
repoclosure Display a list of unresolved dependencies for repositories
repodiff List differences between two sets of repositories
repograph Output a full package dependency graph in dot format
repomanage Manage a directory of rpm packages
reposync download all packages from remote repo
uploadprofile Upload combined profile to Satellite server (list of installed rpms, enabled repositories and modules
General DNF options:
-c [config file], --config [config file]
config file location
-q, --quiet quiet operation
-v, --verbose verbose operation
--version show DNF version and exit
--installroot [path] set install root
--nodocs do not install documentations
--noplugins disable all plugins
--enableplugin [plugin]
enable plugins by name
--disableplugin [plugin]
disable plugins by name
--releasever RELEASEVER
override the value of $releasever in config and repo
files
--setopt SETOPTS set arbitrary config and repo options
--skip-broken resolve depsolve problems by skipping packages
-h, --help, --help-cmd
show command help
--allowerasing allow erasing of installed packages to resolve
dependencies
-b, --best try the best available package versions in
transactions.
--nobest do not limit the transaction to the best candidate
-C, --cacheonly run entirely from system cache, don't update cache
-R [minutes], --randomwait [minutes]
maximum command wait time
-d [debug level], --debuglevel [debug level]
debugging output level
--debugsolver dumps detailed solving results into files
--showduplicates show duplicates, in repos, in list/search commands
-e ERRORLEVEL, --errorlevel ERRORLEVEL
error output level
--obsoletes enables dnf's obsoletes processing logic for upgrade
or display capabilities that the package obsoletes for
info, list and repoquery
--rpmverbosity [debug level name]
debugging output level for rpm
-y, --assumeyes automatically answer yes for all questions
--assumeno automatically answer no for all questions
--enablerepo [repo] Enable additional repositories. List option. Supports
globs, can be specified multiple times.
--disablerepo [repo] Disable repositories. List option. Supports globs, can
be specified multiple times.
--repo [repo], --repoid [repo]
enable just specific repositories by an id or a glob,
can be specified multiple times
--enable enable repos with config-manager command
(automatically saves)
--disable disable repos with config-manager command
(automatically saves)
-x [package], --exclude [package], --excludepkgs [package]
exclude packages by name or glob
--disableexcludes [repo], --disableexcludepkgs [repo]
disable excludepkgs
--repofrompath [repo,path]
label and path to an additional repository to use
(same path as in a baseurl), can be specified multiple
times.
--noautoremove disable removal of dependencies that are no longer
used
--nogpgcheck disable gpg signature checking (if RPM policy allows)
--color COLOR control whether color is used
--refresh set metadata as expired before running the command
-4 resolve to IPv4 addresses only
-6 resolve to IPv6 addresses only
--destdir DESTDIR, --downloaddir DESTDIR
set directory to copy packages to
--downloadonly only download packages
--comment COMMENT add a comment to transaction
--bugfix Include bugfix relevant packages, in updates
--enhancement Include enhancement relevant packages, in updates
--newpackage Include newpackage relevant packages, in updates
--security Include security relevant packages, in updates
--advisory ADVISORY, --advisories ADVISORY
Include packages needed to fix the given advisory, in
updates
--bz BUGZILLA, --bzs BUGZILLA
Include packages needed to fix the given BZ, in
updates
--cve CVES, --cves CVES
Include packages needed to fix the given CVE, in
updates
--sec-severity {Critical,Important,Moderate,Low}, --secseverity {Critical,Important,Moderate,Low}
Include security relevant packages matching the
severity, in updates
--forcearch ARCH Force the use of an architecture
[root@www.cndba.cn ~]#
使用DNF 安装dstat 工具：
[root@www.cndba.cn yum.repos.d]# dnf install dstat
Updating Subscription Management repositories.
Unable to read consumer identity
This system is not registered to Red Hat Subscription Management. You can use subscription-manager to register.
Last metadata expiration check: 0:00:18 ago on Fri 30 Oct 2020 09:15:43 PM CST.
Dependencies resolved.
=======================================================================================================================
Package Architecture Version Repository Size
=======================================================================================================================
Installing:
pcp-system-tools x86_64 5.1.1-3.el8 dave-AppStream 191 k
Installing dependencies:
libuv x86_64 1:1.38.0-1.el8 dave-AppStream 151 k
pcp x86_64 5.1.1-3.el8 dave-AppStream 1.2 M
pcp-conf x86_64 5.1.1-3.el8 dave-AppStream 50 k
pcp-libs x86_64 5.1.1-3.el8 dave-AppStream 536 k
pcp-selinux x86_64 5.1.1-3.el8 dave-AppStream 47 k
python3-pcp x86_64 5.1.1-3.el8 dave-AppStream 167 k
Transaction Summary
=======================================================================================================================
Install 7 Packages
Total size: 2.3 M
Installed size: 6.8 M
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
Preparing : 1/1
Installing : libuv-1:1.38.0-1.el8.x86_64 1/7
Installing : pcp-selinux-5.1.1-3.el8.x86_64 2/7
Running scriptlet: pcp-selinux-5.1.1-3.el8.x86_64 2/7
Installing : pcp-conf-5.1.1-3.el8.x86_64 3/7
Installing : pcp-libs-5.1.1-3.el8.x86_64 4/7
Running scriptlet: pcp-5.1.1-3.el8.x86_64 5/7
Installing : pcp-5.1.1-3.el8.x86_64 5/7
Running scriptlet: pcp-5.1.1-3.el8.x86_64 5/7
Installing : python3-pcp-5.1.1-3.el8.x86_64 6/7
Installing : pcp-system-tools-5.1.1-3.el8.x86_64 7/7
Running scriptlet: pcp-system-tools-5.1.1-3.el8.x86_64 7/7
Verifying : libuv-1:1.38.0-1.el8.x86_64 1/7
Verifying : pcp-5.1.1-3.el8.x86_64 2/7
Verifying : pcp-conf-5.1.1-3.el8.x86_64 3/7
Verifying : pcp-libs-5.1.1-3.el8.x86_64 4/7
Verifying : pcp-selinux-5.1.1-3.el8.x86_64 5/7
Verifying : pcp-system-tools-5.1.1-3.el8.x86_64 6/7
Verifying : python3-pcp-5.1.1-3.el8.x86_64 7/7
Installed products updated.
Installed:
libuv-1:1.38.0-1.el8.x86_64 pcp-5.1.1-3.el8.x86_64 pcp-conf-5.1.1-3.el8.x86_64
pcp-libs-5.1.1-3.el8.x86_64 pcp-selinux-5.1.1-3.el8.x86_64 pcp-system-tools-5.1.1-3.el8.x86_64
python3-pcp-5.1.1-3.el8.x86_64
Complete!
[root@www.cndba.cn yum.repos.d]#
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