【Linux】CentOS 7开机启动过程和关机过程 |
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bootup - 系统启动过程 描述 系统引导涉及许多不同的组件。开机后,系统BIOS将完成最小的硬件初始化,并将控制交给存储在持久存储设备上的引导加载程序。然后,这个引导加载程序将从磁盘(或网络)调用OS内核。在Linux环境下,这个内核(可选)提取并执行一个初始RAM磁盘映像(Initrd),例如由Dracut(8)生成的,它查找根文件系统(可能为此使用systemd)。在找到并挂载根文件系统之后,initrd将控制交给存储在OS映像上的主机的系统管理器(例如systemd),然后该管理器负责检测所有剩余的硬件,挂载所有必要的文件系统并生成所有配置的服务。 在关闭时,系统管理器停止所有服务,卸载所有文件系统(卸载支持它们的存储技术),然后(可选)跳回到initrd卸载根文件系统及其驻留的存储。最后,关闭系统。 系统管理器启动 在启动时,OS映像上的系统管理器负责初始化系统运行所需的文件系统、服务和驱动程序。对于systemd系统来说,这个过程被划分为几个阶段性步骤。 在每个阶段性步骤内部,任务是高度并行的,所以无法准确预测其中的单元的顺序,但是不同阶段之间的先后顺序总是固定的。 当systemd启动系统时,它将激活default.Target的所有依赖项(以及递归地激活这些依赖项的所有依赖项)。通常,default.Target只是Graphical.Target或Multi-user.Target的别名,这取决于系统是配置为图形用户界面,还是配置为文本控制台。为了强制启动流程的规范性以及提高单元的并行性,预先定义了一些具有特定含义的 target 单元。 下面的图表解释了这些具有特定含义的 target 单元之间的依赖关系以及各自在启动流程中的位置。 图中的箭头表示了单元之间的依赖关系与先后顺序,整个图表按照自上而下的时间顺序执行。 重点标识的目标单元经常被用作启动目标。有两种方法可以指定启动目标: (1)使用 systemd.unit= 内核命令行参数(参见systemd手册);(2)使用 default.target 软连接。 因为 timers.target 以异步方式包含在 basic.target 中,所以 timer 单元可以依赖于在 basic.target 之后才启动的服务。 initrd 启动过程 初始的RAM磁盘实现(Initrd)也可以使用systemd来设置。在本例中,initrd内部的引导遵循以下结构。 在initrd内部,也可以将 systemd 用作init程序(由"rdinit="内核引导参数指定),此时 initrd.target 将是默认目标。initrd内部启动流程的上半部分与前一小节 basic.target 之前的部分完全相同,随后的启动流程将如下图所示。 如果成功的将根文件系统挂载到 /sysroot 目录,那么 sysroot.mount 单元将被激活,然后进一步激活 initrd-root-fs.target 目标。 initrd-parse-etc.service 将会分析 /sysroot/etc/fstab 文件以挂载 /usr (若需要)与带有 x-initrd.mount 标记的挂载点。 这些挂载点都将被挂载到 /sysroot 之下,然后流程到达 initrd-fs.target 目标。 再接下来 initrd-cleanup.service 将会使用 /usr/bin/systemctl --no-block isolate initrd-switch-root.target 命令启动 initrd-switch-root.target 目标。因为 isolate 表示立即停止所有在新的目标单元中不需要的进程, 所以此动作实际上是为接下来切换根目录做预先的准备(也就是清理环境)。 最后,激活 initrd-switch-root.service 服务,将系统的根目录切换至 /sysroot 目录。 (之前的流程与上一小节完全相同) : 切换到主机上的操作系统 关机过程 systemd 系统在关机时同样遵循固定的流程,具体如下图所示: 要查看具体的启动顺序可以通过如下命令输入到文件,然后通过浏览器打开查看。 systemd-analyze plot > boot.html 列出所有正在运行的单元,按从初始化开始到启动所花的时间排序。 systemd-analyze blame
下面通过查看日志分析启动过程:
##调用kernel: Oct 14 16:59:56 localhost kernel: Linux version 4.18.11-1.el7.elrepo.x86_64 (mockbuild@Build64R7) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-28) (GCC)) #1 SMP Sat Sep 29 09:42:38 EDT 2018 Oct 14 16:59:56 localhost kernel: Command line: BOOT_IMAGE=/vmlinuz-4.18.11-1.el7.elrepo.x86_64 root=/dev/mapper/rootvg-root ro rd.lvm.lv=rootvg/root rd.lvm.lv=rootvg/swap rhgb quiet … … Oct 14 16:59:56 localhost kernel: SMBIOS 2.5 present. Oct 14 16:59:56 localhost kernel: tsc: Detected 2491.908 MHz processor Oct 14 16:59:56 localhost kernel: acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5 Oct 14 16:59:56 localhost kernel: SCSI subsystem initialized ##提取initramfs: Oct 14 16:59:56 localhost kernel: Unpacking initramfs... Oct 14 16:59:56 localhost kernel: Freeing initrd memory: 29564K
Oct 14 16:59:56 localhost kernel: Block layer SCSI generic (bsg) driver version 0.4 loaded (major 247) Oct 14 16:59:56 localhost kernel: ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver Oct 14 16:59:56 localhost kernel: ehci-pci: EHCI PCI platform driver Oct 14 16:59:56 localhost kernel: ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver Oct 14 16:59:56 localhost kernel: ohci-pci: OHCI PCI platform driver ##使用initramfs启动systemd: Oct 14 16:59:56 localhost systemd[1]: systemd 219 running in system mode. (+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 -SECCOMP +BLKID +ELFUTILS +KMOD +IDN) Oct 14 16:59:56 localhost systemd[1]: Detected virtualization kvm. Oct 14 16:59:56 localhost systemd[1]: Detected architecture x86-64. Oct 14 16:59:56 localhost systemd[1]: Running in initial RAM disk. Oct 14 16:59:56 localhost systemd[1]: Set hostname to . ##到达swap.target: Oct 14 16:59:56 localhost systemd[1]: Reached target Swap. Oct 14 16:59:56 localhost systemd[1]: Starting Swap. Oct 14 16:59:56 localhost systemd[1]: Reached target Local File Systems. Oct 14 16:59:56 localhost systemd[1]: Starting Local File Systems. Oct 14 16:59:56 localhost systemd[1]: Created slice -.slice. Oct 14 16:59:57 localhost systemd: Started Setup Virtual Console. Oct 14 16:59:57 localhost systemd: Started dracut cmdline hook. Oct 14 16:59:57 localhost systemd: Starting dracut pre-udev hook... Oct 14 16:59:58 localhost kernel: device-mapper: uevent: version 1.0.3 Oct 14 16:59:58 localhost systemd: Started dracut pre-udev hook. Oct 14 16:59:58 localhost systemd: Starting udev Kernel Device Manager... Oct 14 16:59:58 localhost systemd-udevd: starting version 219 Oct 14 16:59:58 localhost systemd: Started udev Kernel Device Manager. Oct 14 16:59:58 localhost systemd: Started dracut pre-trigger hook. Oct 14 16:59:58 localhost systemd: Starting udev Coldplug all Devices... Oct 14 16:59:58 localhost systemd: Started udev Coldplug all Devices. ##到达sysinit.target: Oct 14 16:59:58 localhost systemd: Reached target System Initialization. Oct 14 16:59:58 localhost systemd: Starting System Initialization. Oct 14 16:59:58 localhost systemd: Starting dracut initqueue hook... Oct 14 16:59:58 localhost systemd: Starting Show Plymouth Boot Screen... Oct 14 16:59:58 localhost systemd: Mounting Configuration File System... Oct 14 16:59:58 localhost systemd: Mounted Configuration File System. Oct 14 16:59:58 localhost systemd: Started Show Plymouth Boot Screen. Oct 14 16:59:58 localhost systemd: Reached target Paths. Oct 14 16:59:58 localhost systemd: Starting Paths. ##到达basic.target: Oct 14 16:59:58 localhost systemd: Reached target Basic System. Oct 14 16:59:58 localhost systemd: Starting Basic System. Oct 14 16:59:58 localhost kernel: scsi host2: ahci Oct 14 16:59:58 localhost kernel: scsi host3: ahci Oct 14 16:59:59 localhost kernel: scsi 3:0:0:0: Direct-Access ATA VBOX HARDDISK 1.0 PQ: 0 ANSI: 5 Oct 14 16:59:59 localhost kernel: sd 2:0:0:0: [sda] 16777216 512-byte logical blocks: (8.59 GB/8.00 GiB) Oct 14 16:59:59 localhost kernel: sd 2:0:0:0: [sda] Write Protect is off Oct 14 16:59:59 localhost kernel: sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA Oct 14 16:59:59 localhost kernel: sda: sda1 sda2 Oct 14 16:59:59 localhost kernel: sd 2:0:0:0: [sda] Attached SCSI disk Oct 14 17:00:00 localhost systemd: Found device /dev/mapper/rootvg-root. Oct 14 17:00:00 localhost systemd: Starting File System Check on /dev/mapper/rootvg-root... Oct 14 17:00:00 localhost kernel: random: crng init done Oct 14 17:00:00 localhost kernel: random: 7 urandom warning(s) missed due to ratelimiting Oct 14 17:00:00 localhost systemd-fsck: /dev/mapper/rootvg-root: clean, 144286/426544 files, 1062697/1705984 blocks Oct 14 17:00:00 localhost systemd: Started File System Check on /dev/mapper/rootvg-root. Oct 14 17:00:01 localhost systemd: Started dracut initqueue hook. Oct 14 17:00:01 localhost systemd: Reached target Remote File Systems (Pre). Oct 14 17:00:01 localhost systemd: Starting Remote File Systems (Pre). Oct 14 17:00:01 localhost systemd: Reached target Remote File Systems. Oct 14 17:00:01 localhost systemd: Starting Remote File Systems. Oct 14 17:00:01 localhost systemd: Started dracut pre-mount hook. ##将真实的根挂载到/sysroot: Oct 14 17:00:01 localhost systemd: Mounting /sysroot... Oct 14 17:00:01 localhost kernel: EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: (null) Oct 14 17:00:01 localhost systemd: Mounted /sysroot. ##到达initrrd_root_fs.target: Oct 14 17:00:01 localhost systemd: Reached target Initrd Root File System. Oct 14 17:00:01 localhost systemd: Starting Initrd Root File System. Oct 14 17:00:01 localhost systemd: Starting Reload Configuration from the Real Root... Oct 14 17:00:01 localhost systemd: Reloading. Oct 14 17:00:01 localhost systemd: Started Reload Configuration from the Real Root. Oct 14 17:00:01 localhost systemd: Started dracut mount hook. Oct 14 17:00:01 localhost systemd: Reached target Initrd File Systems. Oct 14 17:00:01 localhost systemd: Starting Initrd File Systems. ##到达initrd.target,清理环境为切根做准备,按照启动时相反的顺序停止target: Oct 14 17:00:01 localhost systemd: Reached target Initrd Default Target. Oct 14 17:00:01 localhost systemd: Starting Initrd Default Target. Oct 14 17:00:01 localhost systemd: Starting dracut pre-pivot and cleanup hook... Oct 14 17:00:01 localhost systemd: Started dracut pre-pivot and cleanup hook. Oct 14 17:00:01 localhost systemd: Starting Cleaning Up and Shutting Down Daemons... Oct 14 17:00:01 localhost systemd: Stopped Cleaning Up and Shutting Down Daemons. Oct 14 17:00:01 localhost systemd: Stopped dracut pre-pivot and cleanup hook. Oct 14 17:00:01 localhost systemd: Stopping dracut pre-pivot and cleanup hook... Oct 14 17:00:01 localhost systemd: Stopped target Remote File Systems. Oct 14 17:00:01 localhost systemd: Stopping Remote File Systems. Oct 14 17:00:02 localhost systemd: Stopped target Remote File Systems (Pre). Oct 14 17:00:02 localhost systemd: Stopping Remote File Systems (Pre). Oct 14 17:00:02 localhost systemd: Stopped dracut initqueue hook. Oct 14 17:00:02 localhost systemd: Stopping dracut initqueue hook... Oct 14 17:00:02 localhost systemd: Starting Plymouth switch root service... Oct 14 17:00:02 localhost systemd: Stopped target Initrd Default Target. Oct 14 17:00:02 localhost systemd: Stopping Initrd Default Target. Oct 14 17:00:02 localhost systemd: Stopped target Basic System. Oct 14 17:00:02 localhost systemd: Stopping Basic System. Oct 14 17:00:02 localhost systemd: Stopped target System Initialization. Oct 14 17:00:02 localhost systemd: Stopping System Initialization. Oct 14 17:00:02 localhost systemd: Stopped udev Kernel Device Manager. Oct 14 17:00:02 localhost systemd: Stopped Create Static Device Nodes in /dev. Oct 14 17:00:02 localhost systemd: Stopping Create Static Device Nodes in /dev... Oct 14 17:00:02 localhost systemd: Stopped Create list of required static device nodes for the current kernel. Oct 14 17:00:02 localhost systemd: Stopping Create list of required static device nodes for the current kernel... Oct 14 17:00:02 localhost systemd: Stopped udev Coldplug all Devices. Oct 14 17:00:02 localhost systemd: Stopping udev Coldplug all Devices... Oct 14 17:00:02 localhost systemd: Stopped target Paths. Oct 14 17:00:02 localhost systemd: Stopping Paths. Oct 14 17:00:02 localhost systemd: Stopped target Sockets. Oct 14 17:00:02 localhost systemd: Stopping Sockets. Oct 14 17:00:02 localhost systemd: Closed udev Kernel Socket. Oct 14 17:00:02 localhost systemd: Stopping udev Kernel Socket. Oct 14 17:00:02 localhost systemd: Stopped target Slices. Oct 14 17:00:02 localhost systemd: Stopping Slices. Oct 14 17:00:02 localhost systemd: Stopped target Local File Systems. Oct 14 17:00:02 localhost systemd: Stopping Local File Systems. Oct 14 17:00:02 localhost systemd: Closed udev Control Socket. Oct 14 17:00:02 localhost systemd: Stopping udev Control Socket. Oct 14 17:00:02 localhost systemd: Starting Cleanup udevd DB... Oct 14 17:00:02 localhost systemd: Stopped target Swap. Oct 14 17:00:02 localhost systemd: Stopping Swap. Oct 14 17:00:02 localhost systemd: Stopped target Timers. Oct 14 17:00:02 localhost systemd: Stopping Timers. Oct 14 17:00:02 localhost systemd: Stopped dracut pre-udev hook. Oct 14 17:00:02 localhost systemd: Stopping dracut pre-udev hook... Oct 14 17:00:02 localhost systemd: Stopped dracut cmdline hook. Oct 14 17:00:02 localhost systemd: Stopping dracut cmdline hook... Oct 14 17:00:02 localhost systemd: Stopped Apply Kernel Variables. Oct 14 17:00:02 localhost systemd: Stopping Apply Kernel Variables... Oct 14 17:00:02 localhost systemd: Started Cleanup udevd DB. ##环境清理完成,到达initrd-switch-root.target: Oct 14 17:00:02 localhost systemd: Reached target Switch Root. Oct 14 17:00:02 localhost systemd: Starting Switch Root. Oct 14 17:00:02 localhost systemd: Started Plymouth switch root service. Oct 14 17:00:02 localhost systemd: Starting Switch Root... Oct 14 17:00:02 localhost systemd: Switching root. Oct 14 17:00:02 localhost journal: Journal stopped Oct 14 17:00:07 localhost systemd-journald[132]: Received SIGTERM from PID 1 (systemd). Oct 14 17:00:07 localhost kernel: systemd: 27 output lines suppressed due to ratelimiting Oct 14 17:00:07 localhost kernel: SELinux: Disabled at runtime. Oct 14 17:00:07 localhost systemd[1]: Inserted module 'ip_tables' Oct 14 17:00:07 localhost journal: Journal started ##切根完成,使用真实的根启动systemd: Oct 14 17:00:07 localhost systemd: systemd 219 running in system mode. (+PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 -SECCOMP +BLKID +ELFUTILS +KMOD +IDN) Oct 14 17:00:07 localhost systemd: Detected virtualization kvm. Oct 14 17:00:07 localhost systemd: Detected architecture x86-64. Oct 14 17:00:07 localhost systemd: Set hostname to . Oct 14 17:00:07 localhost systemd: Mounted Debug File System. Oct 14 17:00:07 localhost systemd: Starting Create Static Device Nodes in /dev... Oct 14 17:00:07 localhost kernel: EXT4-fs (dm-0): re-mounted. Opts: (null) Oct 14 17:00:07 localhost systemd: Started Remount Root and Kernel File Systems. Oct 14 17:00:07 localhost systemd: Started Rebuild Dynamic Linker Cache. Oct 14 17:00:07 localhost systemd: Starting Load/Save Random Seed... Oct 14 17:00:07 localhost systemd: Started Rebuild Hardware Database. Oct 14 17:00:07 localhost systemd: Starting udev Coldplug all Devices... Oct 14 17:00:07 localhost systemd: Starting Flush Journal to Persistent Storage... Oct 14 17:00:07 localhost systemd: Starting Configure read-only root support... Oct 14 17:00:07 localhost systemd: Started First Boot Wizard. Oct 14 17:00:07 localhost systemd: Started Apply Kernel Variables. Oct 14 17:00:07 localhost systemd: Started Load/Save Random Seed. Oct 14 17:00:07 localhost systemd: Started LVM2 metadata daemon. Oct 14 17:00:07 localhost systemd: Starting LVM2 metadata daemon... Oct 14 17:00:08 localhost systemd: Started udev Coldplug all Devices. Oct 14 17:00:08 localhost systemd: Starting udev Wait for Complete Device Initialization... Oct 14 17:00:08 localhost systemd: Started Flush Journal to Persistent Storage. Oct 14 17:00:08 localhost kernel: RPC: Registered named UNIX socket transport module. Oct 14 17:00:08 localhost kernel: RPC: Registered udp transport module. Oct 14 17:00:08 localhost kernel: RPC: Registered tcp transport module. Oct 14 17:00:08 localhost kernel: RPC: Registered tcp NFSv4.1 backchannel transport module. Oct 14 17:00:08 localhost systemd: Mounted RPC Pipe File System. Oct 14 17:00:08 localhost systemd: Started Configure read-only root support. Oct 14 17:00:08 localhost systemd: Started Load legacy module configuration. Oct 14 17:00:08 localhost kernel: Installing knfsd (copyright (C) 1996 [email protected]). Oct 14 17:00:08 localhost systemd: Mounted NFSD configuration filesystem. Oct 14 17:00:08 localhost lvm: 2 logical volume(s) in volume group "rootvg" monitored Oct 14 17:00:09 localhost systemd: Started Create Static Device Nodes in /dev. Oct 14 17:00:09 localhost systemd: Starting udev Kernel Device Manager... Oct 14 17:00:09 localhost systemd: Reached target Local File Systems (Pre). Oct 14 17:00:09 localhost systemd: Starting Local File Systems (Pre). Oct 14 17:00:09 localhost systemd-udevd: starting version 219 Oct 14 17:00:09 localhost systemd: Started udev Kernel Device Manager. Oct 14 17:00:11 localhost systemd: Created slice system-lvm2\x2dpvscan.slice. Oct 14 17:00:11 localhost systemd: Starting system-lvm2\x2dpvscan.slice. Oct 14 17:00:11 localhost systemd: Starting LVM2 PV scan on device 8:16... Oct 14 17:00:11 localhost systemd: Found device /dev/mapper/rootvg-swap. Oct 14 17:00:11 localhost systemd: Found device VBOX_HARDDISK 1. Oct 14 17:00:11 localhost systemd: Starting File System Check on /dev/disk/by-uuid/c701b704-6af7-4cc8-ba8f-5050b589faf2... Oct 14 17:00:11 localhost systemd: Starting LVM2 PV scan on device 8:2... Oct 14 17:00:11 localhost systemd: Activating swap /dev/mapper/rootvg-swap... Oct 14 17:00:11 localhost lvm: 2 logical volume(s) in volume group "rootvg" now active Oct 14 17:00:11 localhost systemd: Started LVM2 PV scan on device 8:2. Oct 14 17:00:11 localhost kernel: Adding 1048572k swap on /dev/mapper/rootvg-swap. Priority:-2 extents:1 across:1048572k FS Oct 14 17:00:11 localhost systemd: Activated swap /dev/mapper/rootvg-swap. Oct 14 17:00:11 localhost systemd: Reached target Swap. Oct 14 17:00:11 localhost systemd: Starting Swap. Oct 14 17:00:11 localhost lvm: 1 logical volume(s) in volume group "datavg" now active Oct 14 17:00:11 localhost systemd: Started LVM2 PV scan on device 8:16. Oct 14 17:00:11 localhost systemd: Found device /dev/mapper/datavg-lv_data. Oct 14 17:00:11 localhost systemd: Starting File System Check on /dev/mapper/datavg-lv_data... Oct 14 17:00:11 localhost systemd: Started udev Wait for Complete Device Initialization. Oct 14 17:00:11 localhost systemd: Starting Activation of DM RAID sets... Oct 14 17:00:12 localhost systemd-fsck: /dev/sda1: clean, 699/128016 files, 160136/512000 blocks Oct 14 17:00:12 localhost systemd: Started File System Check on /dev/disk/by-uuid/c701b704-6af7-4cc8-ba8f-5050b589faf2. Oct 14 17:00:12 localhost kernel: EXT4-fs (dm-2): mounted filesystem with ordered data mode. Opts: (null) Oct 14 17:00:12 localhost systemd: Mounting /boot... Oct 14 17:00:12 localhost kernel: EXT4-fs (sda1): mounting ext3 file system using the ext4 subsystem Oct 14 17:00:12 localhost systemd: Started Activation of DM RAID sets. Oct 14 17:00:12 localhost systemd: Reached target Encrypted Volumes. Oct 14 17:00:12 localhost systemd: Starting Encrypted Volumes. Oct 14 17:00:12 localhost kernel: EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null) Oct 14 17:00:12 localhost systemd: Mounted /boot. Oct 14 17:00:12 localhost systemd: Reached target Local File Systems. Oct 14 17:00:12 localhost systemd: Starting Local File Systems. Oct 14 17:00:12 localhost systemd: Starting Tell Plymouth To Write Out Runtime Data... Oct 14 17:00:12 localhost systemd: Starting Import network configuration from initramfs... Oct 14 17:00:12 localhost systemd: Started Reconfigure the system on administrator request. Oct 14 17:00:12 localhost systemd: Started Commit a transient machine-id on disk. Oct 14 17:00:12 localhost systemd: Started Relabel all filesystems, if necessary. Oct 14 17:00:12 localhost systemd: Starting Preprocess NFS configuration... Oct 14 17:00:12 localhost systemd: Started Mark the need to relabel after reboot. Oct 14 17:00:12 localhost systemd: Started Rebuild Journal Catalog. Oct 14 17:00:12 localhost systemd: Started Update is Completed. Oct 14 17:00:12 localhost systemd: Started Preprocess NFS configuration. Oct 14 17:00:12 localhost systemd: Started Tell Plymouth To Write Out Runtime Data. Oct 14 17:00:12 localhost systemd: Started Import network configuration from initramfs. Oct 14 17:00:12 localhost systemd: Starting Create Volatile Files and Directories... Oct 14 17:00:12 localhost systemd: Started Create Volatile Files and Directories. Oct 14 17:00:12 localhost systemd: Starting Security Auditing Service... Oct 14 17:00:13 localhost systemd: Started Security Auditing Service. Oct 14 17:00:13 localhost systemd: Starting Update UTMP about System Boot/Shutdown... Oct 14 17:00:13 localhost systemd: Started Update UTMP about System Boot/Shutdown. ##到达sysinit.target,激活timers.target,paths.target,sockets.target: Oct 14 17:00:13 localhost systemd: Reached target System Initialization. Oct 14 17:00:13 localhost systemd: Starting System Initialization. Oct 14 17:00:13 localhost systemd: Started Daily Cleanup of Temporary Directories. Oct 14 17:00:13 localhost systemd: Starting Daily Cleanup of Temporary Directories. Oct 14 17:00:13 localhost systemd: Reached target Timers. Oct 14 17:00:13 localhost systemd: Starting Timers. Oct 14 17:00:13 localhost systemd: Listening on D-Bus System Message Bus Socket. Oct 14 17:00:13 localhost systemd: Starting D-Bus System Message Bus Socket. Oct 14 17:00:13 localhost systemd: Reached target Paths. Oct 14 17:00:13 localhost systemd: Starting Paths. Oct 14 17:00:13 localhost systemd: Listening on RPCbind Server Activation Socket. Oct 14 17:00:13 localhost systemd: Starting RPCbind Server Activation Socket. Oct 14 17:00:13 localhost systemd: Reached target Sockets. Oct 14 17:00:13 localhost systemd: Starting Sockets. ##到达basic.target,激活multi-user.target或graphical.target: Oct 14 17:00:13 localhost systemd: Reached target Basic System. Oct 14 17:00:13 localhost systemd: Starting Basic System. Oct 14 17:00:13 localhost systemd: Started OpenSSH Server Key Generation. Oct 14 17:00:13 localhost systemd: Starting firewalld - dynamic firewall daemon... Oct 14 17:00:13 localhost systemd: Starting System Logging Service... Oct 14 17:00:13 localhost systemd: Starting Kernel Samepage Merging... Oct 14 17:00:17 localhost systemd: Starting D-Bus System Message Bus... Oct 14 17:00:17 localhost systemd: Started Load CPU microcode update. Oct 14 17:00:17 localhost systemd: Starting Login Service... Oct 14 17:00:17 localhost systemd: Starting NTP client/server... Oct 14 17:00:17 localhost systemd: Started Software RAID monitoring and management. Oct 14 17:00:17 localhost systemd: Starting Dump dmesg to /var/log/dmesg... Oct 14 17:00:17 localhost systemd: Starting Modem Manager... Oct 14 17:00:17 localhost systemd: Started irqbalance daemon. Oct 14 17:00:17 localhost systemd: Starting irqbalance daemon... Oct 14 17:00:17 localhost systemd-logind: New seat seat0. Oct 14 17:00:18 localhost systemd: Started Dump dmesg to /var/log/dmesg. Oct 14 17:00:18 localhost systemd: Started Login Service. Oct 14 17:00:18 localhost systemd: Starting Kernel Samepage Merging (KSM) Tuning Daemon... Oct 14 17:00:18 localhost systemd: Started NTP client/server. Oct 14 17:00:18 localhost systemd: Started GSSAPI Proxy Daemon. Oct 14 17:00:18 localhost systemd: Started RPC security service for NFS server. Oct 14 17:00:18 localhost systemd: Started RPC security service for NFS client and server. Oct 14 17:00:18 localhost systemd: Reached target NFS client services. Oct 14 17:00:18 localhost systemd: Starting NFS client services. Oct 14 17:00:20 localhost systemd: Started firewalld - dynamic firewall daemon. Oct 14 17:00:20 localhost systemd: Starting LSB: Bring up/down networking... Oct 14 17:00:32 localhost network: Bringing up interface enp0s3: [ OK ] Oct 14 17:00:32 localhost systemd: Started LSB: Bring up/down networking. Oct 14 17:00:32 localhost systemd: Reached target Network. Oct 14 17:00:32 localhost systemd: Starting Network. Oct 14 17:00:32 localhost systemd: Starting Dynamic System Tuning Daemon... Oct 14 17:00:32 localhost systemd: Started OpenSSH server daemon. Oct 14 17:00:32 localhost systemd: Starting OpenSSH server daemon... Oct 14 17:00:32 localhost systemd: Reached target Network is Online. Oct 14 17:00:32 localhost systemd: Starting Network is Online. Oct 14 17:00:32 localhost systemd: Starting Postfix Mail Transport Agent... Oct 14 17:00:32 localhost systemd: Starting Vsftpd ftp daemon... Oct 14 17:00:32 localhost systemd: Reached target Remote File Systems (Pre). Oct 14 17:00:32 localhost systemd: Starting Remote File Systems (Pre). Oct 14 17:00:32 localhost systemd: Reached target Remote File Systems. Oct 14 17:00:32 localhost systemd: Starting Remote File Systems. Oct 14 17:00:32 localhost systemd: Starting Permit User Sessions... Oct 14 17:00:32 localhost systemd: Starting Virtualization daemon... Oct 14 17:00:32 localhost systemd: Starting The Apache HTTP Server... Oct 14 17:00:32 localhost systemd: Starting Availability of block devices... Oct 14 17:00:33 localhost systemd: Started Vsftpd ftp daemon. Oct 14 17:00:33 localhost systemd: Started Permit User Sessions. Oct 14 17:00:33 localhost systemd: Started Availability of block devices. Oct 14 17:00:33 localhost systemd: Starting Wait for Plymouth Boot Screen to Quit... Oct 14 17:00:33 localhost systemd: Started Command Scheduler. Oct 14 17:00:33 localhost systemd: Starting Command Scheduler... Oct 14 17:00:33 localhost systemd: Starting GNOME Display Manager... Oct 14 17:00:34 localhost systemd: Started GNOME Display Manager. Oct 14 17:00:35 localhost systemd: Started Dynamic System Tuning Daemon. Oct 14 17:00:35 localhost systemd: Started The Apache HTTP Server. Oct 14 17:00:38 localhost systemd: Started Postfix Mail Transport Agent. Oct 14 17:00:40 localhost systemd: Received SIGRTMIN+21 from PID 294 (plymouthd). Oct 14 17:00:40 localhost systemd: Started Wait for Plymouth Boot Screen to Quit. Oct 14 17:00:40 localhost systemd: Reached target Multi-User System. Oct 14 17:00:40 localhost systemd: Starting Multi-User System. Oct 14 17:00:40 localhost systemd: Reached target Graphical Interface. Oct 14 17:00:40 localhost systemd: Starting Graphical Interface. Oct 14 17:00:40 localhost systemd: Starting Update UTMP about System Runlevel Changes... Oct 14 17:00:40 localhost systemd: Started Stop Read-Ahead Data Collection 10s After Completed Startup. Oct 14 17:00:40 localhost systemd: Started Update UTMP about System Runlevel Changes. Oct 14 17:00:40 localhost systemd: Startup finished in 1.248s (kernel) + 6.518s (initrd) + 37.578s (userspace) = 45.345s. 至此,启动完成。
查看initramfs内容:
#mkdir /tmp/initramfs # cp /boot/initramfs-3.10.0-327.el7.x86_64.img /tmp/initramfs # /usr/lib/dracut/skipcpio initramfs-3.10.0-327.el7.x86_64.img | zcat | cpio -id --no-absolute-filenames 解压后的目录内容如下: total 18676 -rw-r--r-- 1 root root 19076118 Oct 14 21:28 initramfs-3.10.0-327.el7.x86_64.img drwxr-xr-x 2 root root 4096 Oct 14 21:29 sys -rwxr-xr-x 1 root root 3041 Oct 14 21:29 shutdown lrwxrwxrwx 1 root root 7 Oct 14 21:29 lib -> usr/lib lrwxrwxrwx 1 root root 23 Oct 14 21:29 init -> usr/lib/systemd/systemd drwxr-xr-x 2 root root 4096 Oct 14 21:29 var drwxr-xr-x 2 root root 4096 Oct 14 21:29 tmp drwxr-xr-x 2 root root 4096 Oct 14 21:29 sysroot lrwxrwxrwx 1 root root 8 Oct 14 21:29 sbin -> usr/sbin drwxr-xr-x 2 root root 4096 Oct 14 21:29 run drwxr-xr-x 2 root root 4096 Oct 14 21:29 root drwxr-xr-x 2 root root 4096 Oct 14 21:29 proc lrwxrwxrwx 1 root root 9 Oct 14 21:29 lib64 -> usr/lib64 drwxr-xr-x 12 root root 4096 Oct 14 21:29 etc drwxr-xr-x 2 root root 4096 Oct 14 21:29 dev lrwxrwxrwx 1 root root 7 Oct 14 21:29 bin -> usr/bin drwxr-xr-x 7 root root 4096 Oct 14 21:29 usr
init是链接到systemd,systemd是Linux的第一个进程(PID=1)。 |
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