适用于：✔️ Linux VM
错误的 HugePages 配置可能会导致 Linux 虚拟机（VM）中的启动问题，从而导致内存分配问题。 本文提供了启动问题的原因和解决方案。
先决条件
- 访问 Azure 串行控制台。
- 熟悉 Linux 命令和系统管理。
现象
由于 HugePages 配置不正确，可能会出现以下问题：
将 Linux VM 从本地迁移到 Azure 后，VM 无法正确启动。
缩小 Azure Linux VM 的大小后，它无法正确启动。
使用某些服务启动 Azure Linux VM 时，它无法正常启动。 登录提示显示缓慢，无法登录。
查看各种 Linux VM（Red Hat、Oracle、SUSE 或 Ubuntu）的串行控制台日志时，通常会发现以下问题：
- 无法启动 udev 内核设备管理器。
- 等待特定设备超时。
- 本地文件系统和紧急模式的依赖项故障。
- 由 systemd-udevd 服务或其他进程导致的内存不足错误。
- 无法启动各种网络和系统服务。
- 系统在登录或启动时挂起。
下面是一些日志示例：
输出 1
[FAILED] Failed to start udev Kernel Device Manager. See 'systemctl status systemd-udevd.service' for details. [FAILED] Failed to start udev Kernel Device Manager. See 'systemctl status systemd-udevd.service' for details. [ TIME ] Timed out waiting for device dev-di...\x2db5ea\x2dcc7e4fcafaad.device. [DEPEND] Dependency failed for /boot. [DEPEND] Dependency failed for Local File Systems. [DEPEND] Dependency failed for Relabel all filesystems, if necessary. [DEPEND] Dependency failed for Mark the need to relabel after reboot. [DEPEND] Dependency failed for Migrate local... structure to the new structure. [DEPEND] Dependency failed for /boot/efi. [ TIME ] Timed out waiting for device dev-ttyS0.device. [ TIME ] Timed out waiting for device dev-di...-azure_resource\x2dpart1.device. [DEPEND] Dependency failed for File System C...disk/cloud/azure_resource-part1. [ TIME ] Timed out waiting for device dev-disk-by\x2duuid-D147\x2d2497.device. [ OK ] Reached target Timers. [ OK ] Reached target Login Prompts. [ OK ] Reached target Cloud-init target. [ OK ] Reached target Network (Pre). [ OK ] Reached target Cloud-config availability. [ OK ] Reached target Network. [ OK ] Reached target Network is Online. [FAILED] Failed to start Crash recovery kernel arming. See 'systemctl status kdump.service' for details. [ OK ] Reached target Paths. [ OK ] Reached target Sockets. [FAILED] Failed to start Import network configuration from initramfs. See 'systemctl status rhel-import-state.service' for details. [FAILED] Failed to start Create Volatile Files and Directories. See 'systemctl status systemd-tmpfiles-setup.service' for details. [FAILED] Failed to start Emergency Shell. See 'systemctl status emergency.service' for details. [DEPEND] Dependency failed for Emergency Mode. [FAILED] Failed to start Tell Plymouth To Write Out Runtime Data. See 'systemctl status plymouth-read-write.service' for details. [FAILED] Failed to start Security Auditing Service. See 'systemctl status auditd.service' for details. [FAILED] Failed to start Update UTMP about System Boot/Shutdown. See 'systemctl status systemd-update-utmp.service' for details. [DEPEND] Dependency failed for Update UTMP about System Runlevel Changes. [ OK ] Started Monitoring of LVM2 mirrors,...ng dmeventd or progress polling. [ OK ] Reached target Local File Systems (Pre).输出 2
[ 385.665208][ T709] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090008 12/07/2018 [ 385.675431][ T709] Call Trace: [ 385.678028][ T709] <TASK> [ 385.680574][ T709] dump_stack_lvl+0x45/0x5b [ 385.684222][ T709] dump_header+0x4a/0x220 [ 385.695420][ T709] oom_kill_process+0xe8/0x140 [ 385.710672][ T709] out_of_memory+0x113/0x580 [ 385.716986][ T709] __alloc_pages_slowpath.constprop.112+0x980/0xc70 [ 385.723770][ T709] __alloc_pages+0x2d9/0x320 [ 385.761856][ T709] pagecache_get_page+0x1a8/0x480 [ 385.774844][ T709] filemap_fault+0x4c1/0xa30 [ 385.779807][ T709] ? next_uptodate_page+0x11e/0x270 [ 385.785288][ T709] __xfs_filemap_fault+0x5c/0x280 [xfs 2321eaa9ab2ad44a628250c07d85c25988bf91a0] [ 385.805707][ T709] __do_fault+0x31/0xc0 [ 385.809628][ T709] __handle_mm_fault+0xd64/0x1220 [ 385.838902][ T709] ? switch_fpu_return+0x49/0xd0 [ 385.843779][ T709] handle_mm_fault+0xd7/0x290 [ 385.848516][ T709] do_user_addr_fault+0x1eb/0x730 [ 385.853696][ T709] exc_page_fault+0x67/0x150 [ 385.858809][ T709] ? asm_exc_page_fault+0x8/0x30 [ 385.865062][ T709] asm_exc_page_fault+0x1e/0x30 [ 385.879856][ T709] RIP: 0033:0x55dc84c10950 [ 385.891682][ T709] Code: Unable to access opcode bytes at RIP 0x55dc84c10926. [ 385.898248][ T709] RSP: 002b:00007ffeaf98d1e8 EFLAGS: 00010213 [ 385.904334][ T709] RAX: 00007f3402d98ce0 RBX: 000055dc84f47ff0 RCX: 00007ffeaf98d2e0 [ 385.918600][ T709] RDX: 0000000000000001 RSI: 0000000000000003 RDI: 000055dc84f47ff0 [ 385.926905][ T709] RBP: 00007ffeaf98d210 R08: 0000000016fae5c5 R09: 0000000000000002 [ 385.933967][ T709] R10: 00007ffeaf98d110 R11: 011d994f1f52633a R12: 00007ffeaf98d208 [ 385.942056][ T709] R13: 000055dc84f47620 R14: 0000000000000000 R15: 0000000000000001 [ 385.949403][ T709] </TASK> [ 385.952126][ T709] Mem-Info: [ 385.955048][ T709] active_anon:167 inactive_anon:10940 isolated_anon:0 [ 385.955048][ T709] active_file:15 inactive_file:362 isolated_file:0 [ 385.955048][ T709] unevictable:788 dirty:0 writeback:0 [ 385.955048][ T709] slab_reclaimable:7132 slab_unreclaimable:6898 [ 385.955048][ T709] mapped:448 shmem:5085 pagetables:634 bounce:0 [ 385.955048][ T709] free:29370 free_pcp:1347 free_cma:0 [ 385.993037][ T709] Node 0 active_anon:668kB inactive_anon:43760kB active_file:60kB inactive_file:3304kB unevictable:3152kB isolated(anon):0kB isolated(file):0kB mapped:2140kB dirty:0kB writeback:0kB shmem:20340kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 4096kB writeback_tmp:0kB kernel_stack:2352kB pagetables:2536kB all_unreclaimable? yes [ 386.023392][ T709] Node 0 DMA free:14304kB boost:0kB min:128kB low:160kB high:192kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15360kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB [ 386.050587][ T709] lowmem_reserve[]: 0 888 7864 7864 7864 [ 386.056325][ T709] Node 0 DMA32 free:35408kB boost:0kB min:7616kB low:9520kB high:11424kB reserved_highatomic:0KB active_anon:0kB inactive_anon:12kB active_file:44kB inactive_file:60kB unevictable:0kB writepending:0kB present:1032128kB managed:966592kB mlocked:0kB bounce:0kB free_pcp:296kB local_pcp:296kB free_cma:0kB [ 386.083493][ T709] lowmem_reserve[]: 0 0 6976 6976 6976 [ 386.088634][ T709] Node 0 Normal free:64832kB boost:0kB min:59836kB low:74792kB high:89748kB reserved_highatomic:4096KB active_anon:668kB inactive_anon:43748kB active_file:56kB inactive_file:4392kB unevictable:3152kB writepending:0kB present:7340032kB managed:7151896kB mlocked:80kB bounce:0kB free_pcp:5096kB local_pcp:4848kB free_cma:0kB [ 386.119264][ T709] lowmem_reserve[]: 0 0 0 0 0 [ 386.124090][ T709] Node 0 DMA: 0*4kB 0*8kB 0*16kB 1*32kB (U) 1*64kB (U) 1*128kB (U) 1*256kB (U) 1*512kB (U) 1*1024kB (U) 2*2048kB (UM) 2*4096kB (M) = 14304kB [ 386.139306][ T709] Node 0 DMA32: 12*4kB (UME) 10*8kB (UME) 5*16kB (UME) 4*32kB (UME) 4*64kB (UME) 4*128kB (UME) 4*256kB (UME) 1*512kB (E) 2*1024kB (ME) 3*2048kB (UME) 6*4096kB (M) = 35408kB [ 386.158584][ T709] Node 0 Normal: 284*4kB (UME) 246*8kB (UME) 268*16kB (UME) 212*32kB (UME) 141*64kB (UME) 77*128kB (ME) 36*256kB (UME) 30*512kB (UME) 9*1024kB (UM) 0*2048kB 0*4096kB = 66848kB [ 386.183411][ T709] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=1048576kB [ 386.194414][ T709] Node 0 hugepages_total=3833 hugepages_free=3833 hugepages_surp=0 hugepages_size=2048kB [ 386.205473][ T709] 5679 total pagecache pages [ 386.210473][ T709] 0 pages in swap cache [ 386.214075][ T709] Swap cache stats: add 0, delete 0, find 0/0 [ 386.221319][ T709] Free swap = 0kB [ 386.226581][ T709] Total swap = 0kB [ 386.230305][ T709] 2097038 pages RAM [ 386.234587][ T709] 0 pages HighMem/MovableOnly [ 386.239784][ T709] 63576 pages reserved [ 386.243950][ T709] 0 pages cma reserved [ 386.248253][ T709] 0 pages hwpoisoned [ 386.252967][ T709] Tasks state (memory values in pages): [ 386.259648][ T709] [ pid ] uid tgid total_vm rss pgtables_bytes swapents oom_score_adj name [ 386.270760][ T709] [ 709] 0 709 19824 674 188416 0 -250 systemd-journal [ 386.283947][ T709] [ 720] 0 720 21762 503 192512 0 -1000 systemd-udevd [ 386.293745][ T709] [ 800] 0 800 24367 93 86016 0 -1000 auditd [ 386.303305][ T709] [ 816] 499 816 12221 186 139264 0 -900 dbus-daemon [ 386.313051][ T709] [ 818] 0 818 1943 180 61440 0 0 hv_kvp_daemon [ 386.325447][ T709] [ 820] 0 820 23486 65 86016 0 0 irqbalance [ 386.336826][ T709] [ 825] 489 825 69833 98 159744 0 0 nscd [ 386.347420][ T709] [ 854] 0 854 17766 240 180224 0 0 systemd-logind [ 386.357018][ T709] [ 973] 0 973 10708 313 131072 0 0 wickedd-auto4 [[0;32m OK [[ 386.369228][ T709] [ 985] 0 985 10709 317 122880 0 0 wickedd-dhcp4 [ 386.380633][ T709] [ 986] 0 986 10709 314 122880 0 0 wickedd-dhcp6 0m] Started [0;[ 386.393786][ T709] [ 989] 0 989 10738 345 131072 0 0 wickedd 1;39mBackup of /[ 386.404982][ T709] [ 1002] 0 1002 10715 326 126976 0 0 wickedd-nanny etc/sysconfig[0[ 386.417223][ T709] [ 1048] 0 1048 3847 79 73728 0 0 bash m.[ 386.428454][ T709] [ 1053] 0 1053 23636 109 192512 0 0 gc_linux_servic [ 386.441650][ T709] [ 1063] 0 1063 123508 1761 143360 0 -1000 auomscollect [ 386.452738][ T709] [ 1080] 0 1080 3114 75 69632 0 0 netconfig [ 386.465579][ T709] [ 1082] 0 1082 3408 364 69632 0 0 netconfig [ 386.480799][ T709] [ 1103] 0 1103 3408 364 61440 0 0 netconfig [ 386.491063][ T709] [ 1104] 0 1104 3213 172 73728 0 0 dns-resolver [ 386.508797][ T709] [ 1105] 0 1105 3213 172 65536 0 0 dns-resolver [ 386.520964][ T709] [ 1106] 0 1106 3213 173 65536 0 0 dns-resolver [ 386.531198][ T709] [ 1107] 0 1107 7028 29 86016 0 0 systemctl [ 386.542406][ T709] oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/,task=netconfig,pid=1082,uid=0 [ 386.559765][ T709] Out of memory: Killed process 1082 (netconfig) total-vm:13632kB, anon-rss:1456kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtables:68kB oom_score_adj:0 [ 386.582247][ T32] oom_reaper: reaped process 1082 (netconfig), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB [[0;32m OK [0m] Started [0;1;39mCheck if mainboard battery is Ok[0m.输出 3
[ 0.847506] Kernel panic - not syncing: System is deadlocked on memory [ 0.847506] [ 0.851071] CPU: 4 PID: 1 Comm: systemd Not tainted 4.18.0-553.22.1.el8_10.x86_64 #1 [ 0.854342] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 08/23/2024 [ 0.859012] Call Trace: [ 0.860073] dump_stack+0x41/0x60 [ 0.861499] panic+0xe7/0x2ac [ 0.862980] out_of_memory.cold.36+0x5e/0x7e [ 0.864883] __alloc_pages_slowpath+0xbf0/0xcd0 [ 0.867007] __alloc_pages_nodemask+0x2e2/0x330 [ 0.868934] new_slab+0x3f4/0x4f0 [ 0.870369] ? srso_alias_return_thunk+0x5/0xfcdfd [ 0.872421] ? pcpu_block_refresh_hint+0x7f/0xb0 [ 0.874357] ___slab_alloc+0x3a3/0x950 [ 0.875968] ? __kernfs_new_node+0x5d/0x1e0 [ 0.877790] ? srso_alias_return_thunk+0x5/0xfcdfd [ 0.880110] ? __kernfs_iattrs.isra.7+0x3b/0xc0 [ 0.882048] ? kernfs_xattr_get+0x1d/0x50 [ 0.883778] ? __kernfs_new_node+0x5d/0x1e0 [ 0.885589] kmem_cache_alloc+0x252/0x280 [ 0.887343] __kernfs_new_node+0x5d/0x1e0 [ 0.889081] ? string+0x44/0x60 [ 0.890452] ? srso_alias_return_thunk+0x5/0xfcdfd [ 0.892504] ? vsnprintf+0x340/0x520 [ 0.894049] kernfs_new_node+0x31/0x50 [ 0.895869] __kernfs_create_file+0x30/0xc0 [ 0.897924] cgroup_addrm_files+0x143/0x340 [ 0.900250] ? alloc_shrinker_info+0xca/0x100 [ 0.902675] css_populate_dir+0x86/0x140 [ 0.904900] cgroup_apply_control_enable+0xed/0x310 [ 0.907558] cgroup_mkdir+0x1c2/0x490 [ 0.909521] kernfs_iop_mkdir+0x5a/0xa0 [ 0.911781] vfs_mkdir+0x11b/0x1e0 [ 0.913579] do_mkdirat+0xec/0x120 [ 0.915356] do_syscall_64+0x5b/0x1a0 [ 0.917315] entry_SYSCALL_64_after_hwframe+0x66/0xcb [ 0.919947] RIP: 0033:0x7fd43f794d4b [ 0.921829] Code: 73 01 c3 48 8b 0d 3d 71 39 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 0d 71 39 00 f7 d8 64 89 01 48 [ 0.932128] RSP: 002b:00007ffd7e0fac28 EFLAGS: 00000206 ORIG_RAX: 0000000000000053 [ 0.936149] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fd43f794d4b [ 0.939935] RDX: 00007ffd7e0faaf0 RSI: 00000000000001ed RDI: 000055b707c3c410 [ 0.945738] RBP: 00007ffd7e0fac70 R08: 0000000000000022 R09: 002f70756f726763 [ 0.949630] R10: 0000000000000100 R11: 0000000000000206 R12: 000055b707c1e500 [ 0.953284] R13: 00000000000000a0 R14: 00007fd441021a7e R15: 0000000000000020 [ 0.958110] Kernel Offset: 0x35000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 0.964040] fbcon: Taking over console [ 0.966128] ---[ end Kernel panic - not syncing: System is deadlocked on memory [ 0.966128] ]--
原因
出现此问题的原因是所有可用内存都保留给 HugePages，因此服务器没有足够的可用内存来启动和执行进程。
例如，如果在 /etc/sysctl.conf 文件中将 HugePages 配置参数vm.nr_hugepages设置为 65536，而 VM 只有 16 GB 的总内存，则此配置消耗 134,217,728 KB 内存，超过 VM 内存，导致内存不足（OOM）条件。
解决方法
重要
查看 VM 具有多少内存以及设置了多少 HugePages。 例如，在某些情况下，如果系统需要 16 GB 的 HugePages，并且 VM 只有 16 GB RAM，则内存不足导致 VM 无法启动。 在这种情况下，建议将 VM 大小升级到至少 32 GB RAM。 有关 VM 和数据库需要的 HugePages 的详细信息，请参阅 Oracle Community。
要解决该问题，请执行以下步骤：
使用以下方法之一访问 VM：
如果串行控制台正常工作，请使用 Azure 串行控制台 在单用户模式下启动 VM。
使用 Azure VM 修复命令修复 Linux VM。
（脱机方法） 创建救援 VM 以手动修复 VM 启动问题。
如果在步骤 1 中使用 Azure VM 修复命令或脱机方法，请按照 Linux 救援 VM 中的 Chroot 环境中引入的 chroot 过程进行操作。
使用文本编辑器打开 /etc/sysctl.conf 或 /etc/sysctl.conf.d/*/ 文件，例如
vi：sudo vi /etc/sysctl.conf找到设置
vm.nr_hugepages参数的位置：vm.nr_hugepages=<the number of HugePages>注释掉行或调整
vm.nr_hugepages值以平衡性能和内存分配。保存更改并退出文本编辑器。
根据操作系统分发手动 重新生成缺少的 initramfs。
重新启动 VM 以应用更改：
sudo reboot监视 VM，确保其正确启动，服务按预期启动。
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