udev根据系统中的硬件设备的状态动态更新设备，通过对内核产生的设备名增加别名的方式来达到不管设备连接的顺序而维持一个统一的设备名的目的。udev可以根据设备的其他信息如总线（bus），生产商（vendor）等不同来区分不同的设备，并产生设备文件。udev是硬件平台无关的，属于user space的进程，它脱离驱动层的关联而建立在操作系统之上，遵循Linux Standard Base （LSB）设备命名方法，但也可以自定义命名
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 [mingxu.xie@cn-aux-cc udev]$ ll -R .: total 8 drwxr-xr-x 2 root root 4096 Jun 6 02:58 rules.d -rw-r--r-- 1 root root 218 Mar 19 2014 udev.conf ./rules.d: total 32 -rw-r--r-- 1 root root 640 Jul 31 2016 51-ec2-hvm-devices.rules -rw-r--r-- 1 root root 641 Jul 31 2016 52-ec2-vcpu.rules -rw-r--r-- 1 root root 740 Jul 31 2016 53-ec2-network-interfaces.rules -rw-r--r-- 1 root root 680 Jul 31 2016 60-cdrom_id.rules -rw-r--r-- 1 root root 326 Apr 26 2016 60-raw.rules -rw-r--r-- 1 root root 1343 Jul 31 2016 70-ec2-nvme-devices.rules -rw-r--r-- 1 root root 1424 Jul 31 2016 75-persistent-net-generator.rules -rwxr-xr-x 1 root root 343 Aug 21 2016 80-docker.rules # 主配置 /etc/udev/udev.conf udev_root="/dev/" udev_rules="/etc/udev/rules.d/" #rule规则的文件命名第一段为执行顺序，同rc脚本 [mingxu.xie@cn-aux-cc udev]$ cat rules.d/53-ec2-network-interfaces.rules # Copyright (C) 2012 Amazon.com, Inc. or its affiliates. # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"). # You may not use this file except in compliance with the License. # A copy of the License is located at # # http://aws.amazon.com/apache2.0/ # # or in the "license" file accompanying this file. This file is # distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS # OF ANY KIND, either express or implied. See the License for the # specific language governing permissions and limitations under the # License. ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth*", IMPORT{program}="/bin/sleep 1" SUBSYSTEM=="net", KERNEL=="eth*", RUN+="/etc/sysconfig/network-scripts/ec2net.hotplug"
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 #监听一个docker run -it --rm nginx bash容器启动的设备变化情况，如下 [mingxu.xie@cn-aux-cc udev]$ udevadm monitor monitor will print the received events for: UDEV - the event which udev sends out after rule processing KERNEL - the kernel uevent KERNEL[240932.229041] add /devices/virtual/bdi/253:8 (bdi) KERNEL[240932.229579] add /devices/virtual/block/dm-8 (block) UDEV [240932.229612] add /devices/virtual/bdi/253:8 (bdi) UDEV [240932.229641] add /devices/virtual/block/dm-8 (block) KERNEL[240932.248388] change /devices/virtual/block/dm-8 (block) UDEV [240932.272904] change /devices/virtual/block/dm-8 (block) KERNEL[240932.425971] remove /devices/virtual/block/dm-8 (block) UDEV [240932.428073] remove /devices/virtual/block/dm-8 (block) KERNEL[240932.456141] remove /devices/virtual/bdi/253:8 (bdi) KERNEL[240932.456261] remove /devices/virtual/block/dm-8 (block) UDEV [240932.456380] remove /devices/virtual/bdi/253:8 (bdi) UDEV [240932.456419] remove /devices/virtual/block/dm-8 (block) KERNEL[240932.469307] add /devices/virtual/bdi/253:8 (bdi) KERNEL[240932.469384] add /devices/virtual/block/dm-8 (block) UDEV [240932.469657] add /devices/virtual/bdi/253:8 (bdi) UDEV [240932.469691] add /devices/virtual/block/dm-8 (block) KERNEL[240932.488228] change /devices/virtual/block/dm-8 (block) UDEV [240932.504203] change /devices/virtual/block/dm-8 (block) KERNEL[240932.636785] remove /devices/virtual/block/dm-8 (block) UDEV [240932.638755] remove /devices/virtual/block/dm-8 (block) KERNEL[240932.676137] remove /devices/virtual/bdi/253:8 (bdi) KERNEL[240932.676245] remove /devices/virtual/block/dm-8 (block) UDEV [240932.676367] remove /devices/virtual/bdi/253:8 (bdi) UDEV [240932.676420] remove /devices/virtual/block/dm-8 (block) KERNEL[240932.683098] add /devices/virtual/bdi/253:8 (bdi) KERNEL[240932.683204] add /devices/virtual/block/dm-8 (block) UDEV [240932.683384] add /devices/virtual/bdi/253:8 (bdi) UDEV [240932.683582] add /devices/virtual/block/dm-8 (block) KERNEL[240932.696227] change /devices/virtual/block/dm-8 (block) UDEV [240932.712517] change /devices/virtual/block/dm-8 (block) KERNEL[240932.793677] add /devices/virtual/net/veth4d1712b (net) KERNEL[240932.793699] add /devices/virtual/net/veth4d1712b/queues/rx-0 (queues) KERNEL[240932.793727] add /devices/virtual/net/veth4d1712b/queues/tx-0 (queues) KERNEL[240932.793908] add /devices/virtual/net/veth17f6e3e (net) KERNEL[240932.793930] add /devices/virtual/net/veth17f6e3e/queues/rx-0 (queues) KERNEL[240932.793942] add /devices/virtual/net/veth17f6e3e/queues/tx-0 (queues) UDEV [240932.827598] add /devices/virtual/net/veth4d1712b (net) UDEV [240932.827843] add /devices/virtual/net/veth4d1712b/queues/rx-0 (queues) UDEV [240932.828121] add /devices/virtual/net/veth4d1712b/queues/tx-0 (queues) KERNEL[240932.849171] add /kernel/slab/:A-0000200/cgroup/vm_area_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849196] add /kernel/slab/:A-0000064/cgroup/anon_vma_chain(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.849211] add /kernel/slab/:A-0000200/cgroup/vm_area_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849225] add /kernel/slab/anon_vma/cgroup/anon_vma(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849238] add /kernel/slab/:aA-0000192/cgroup/dentry(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849252] add /kernel/slab/proc_inode_cache/cgroup/proc_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.849269] add /kernel/slab/:A-0000064/cgroup/anon_vma_chain(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849436] add /kernel/slab/:0000064/cgroup/kmalloc-64(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.849455] add /kernel/slab/shmem_inode_cache/cgroup/shmem_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.849709] add /kernel/slab/proc_inode_cache/cgroup/proc_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.850033] add /kernel/slab/anon_vma/cgroup/anon_vma(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.850374] add /kernel/slab/shmem_inode_cache/cgroup/shmem_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.850527] add /kernel/slab/:aA-0000192/cgroup/dentry(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.852368] add /kernel/slab/:0000064/cgroup/kmalloc-64(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.854849] add /kernel/slab/:0000192/cgroup/kmalloc-192(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.854871] add /kernel/slab/:0001024/cgroup/kmalloc-1024(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855103] add /kernel/slab/radix_tree_node/cgroup/radix_tree_node(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.855120] add /kernel/slab/:0000192/cgroup/kmalloc-192(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855133] add /kernel/slab/:A-0000192/cgroup/cred_jar(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855145] add /kernel/slab/:A-0002048/cgroup/mm_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855158] add /kernel/slab/mqueue_inode_cache/cgroup/mqueue_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855170] add /kernel/slab/sock_inode_cache/cgroup/sock_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855359] add /kernel/slab/:A-0009664/cgroup/task_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.855395] add /kernel/slab/:A-0002048/cgroup/mm_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855410] add /kernel/slab/:A-0000704/cgroup/files_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.855445] add /kernel/slab/mqueue_inode_cache/cgroup/mqueue_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855461] add /kernel/slab/sighand_cache/cgroup/sighand_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.855474] add /kernel/slab/:0001024/cgroup/kmalloc-1024(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855487] add /kernel/slab/:A-0001024/cgroup/signal_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.855499] add /kernel/slab/:A-0000128/cgroup/pid(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.855512] add /kernel/slab/radix_tree_node/cgroup/radix_tree_node(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.856010] add /kernel/slab/sock_inode_cache/cgroup/sock_inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.856029] add /kernel/slab/:A-0009664/cgroup/task_struct(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.856045] add /kernel/slab/sighand_cache/cgroup/sighand_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.856077] add /kernel/slab/:0000256/cgroup/kmalloc-256(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.856092] add /kernel/slab/:A-0000704/cgroup/files_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.856104] add /kernel/slab/:0000512/cgroup/kmalloc-512(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.856188] add /kernel/slab/:A-0000128/cgroup/pid(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.857080] add /kernel/slab/:A-0000192/cgroup/cred_jar(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.857105] add /kernel/slab/:A-0001024/cgroup/signal_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.857126] add /kernel/slab/:0000256/cgroup/kmalloc-256(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.857140] add /kernel/slab/:0000512/cgroup/kmalloc-512(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.862157] add /kernel/slab/xfs_inode/cgroup/xfs_inode(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.862348] add /kernel/slab/xfs_inode/cgroup/xfs_inode(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240932.863008] add /kernel/slab/inode_cache/cgroup/inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.863179] add /kernel/slab/inode_cache/cgroup/inode_cache(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240932.932564] add /devices/virtual/net/veth17f6e3e (net) UDEV [240932.932779] add /devices/virtual/net/veth17f6e3e/queues/rx-0 (queues) UDEV [240932.932880] add /devices/virtual/net/veth17f6e3e/queues/tx-0 (queues) KERNEL[240932.960183] remove /devices/virtual/net/veth4d1712b (net) UDEV [240932.982851] remove /devices/virtual/net/veth4d1712b (net) KERNEL[240933.089679] add /kernel/slab/:0000008/cgroup/kmalloc-8(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240933.089933] add /kernel/slab/:0000008/cgroup/kmalloc-8(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240933.150833] add /kernel/slab/:0002048/cgroup/kmalloc-2048(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) KERNEL[240933.150863] add /kernel/slab/:0000096/cgroup/kmalloc-96(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240933.151052] add /kernel/slab/:0002048/cgroup/kmalloc-2048(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup) UDEV [240933.151130] add /kernel/slab/:0000096/cgroup/kmalloc-96(990:53b4e439f50242461e4c1246718e12d769d3bc4752c0f0ed5bc4f317bb4feb3d) (cgroup)
