rhel直接用yum install 是没有python3的
网上找了很多方法，一般是手动编译，但好麻烦
最终找到了办法就是安装ius源
但网上的ius源都是错的，根本无法使用
正确方法：
rpm -ivh https://repo.ius.io/ius-release-el7.rpm yum install python36
linux
Error: Connection activation failed: The master connection ‘ens18’ is not compatible with ‘ib2’
问题起因：
虚拟机中更换了硬件网络类型，由原来的10G网卡更换为IB卡
虚拟机中ib卡状态是up正常的，但并无法工作，当使用ifup启动该ib卡时出现如下错误
Error: Connection activation failed: The master connection 'ens18' is not compatible with 'ib2'
经过排查，因为启用了NetworkManager组件
ifup脚本中实际调用的是
nmcli con up uuid 9c106a1a-4b4c-45ee-b7c7-ded7a57135b0
而无论你如何更改ifcfg文件中的UUID，该命令都会失败，具体NM是如何映射的还不清楚。
最终命用命令
nmcli con reload
解决问题
找到SM Master节点所在的机器的方法
通过sminfo确认master的guid，然后使用ibstat在每台局域网中的机器上执行，找到对应的Port
sminfo
sminfo: sm lid 62 sm guid <strong>0x98039b0300e24101</strong>, activity count 1932118 priority 14 state 3 SMINFO_MASTER
ibstat
CA 'mlx4_0'
CA type: MT4099
Number of ports: 2
Firmware version: 2.36.5150
Hardware version: 1
Node GUID: 0x0002c903001996a0
System image GUID: 0x0002c903001996a3
Port 1:
State: Active
Physical state: LinkUp
Rate: 40
Base lid: 67
LMC: 0
SM lid: 62
Capability mask: 0x0251486a
Port GUID: 0x0002c903001996a1
Link layer: InfiniBand
Port 2:
State: Active
Physical state: LinkUp
Rate: 40
Base lid: 64
LMC: 0
SM lid: 62
Capability mask: 0x02514868
Port GUID: 0x0002c903001996a2
Link layer: InfiniBand
CA 'mlx4_1'
CA type: MT4099
Number of ports: 2
Firmware version: 2.42.5000
Hardware version: 1
Node GUID: 0x0002c90300449310
System image GUID: 0x0002c90300449313
Port 1:
State: Active
Physical state: LinkUp
Rate: 40
Base lid: 5
LMC: 0
SM lid: 62
Capability mask: 0x02514868
Port GUID: 0x0002c90300449311
Link layer: InfiniBand
Port 2:
State: Active
Physical state: LinkUp
Rate: 40
Base lid: 9
LMC: 0
SM lid: 62
Capability mask: 0x02514868
Port GUID: 0x0002c90300449312
Link layer: InfiniBand
Centos环境中更新grub 选项的正确方法
新公司的工作是开发管理VM的插件，类似于实现nova中的libvirtdriver
在处理SR-IOV设备时需要打开宿主机的iommu
网上的方法就是修改grub
grub在centos中有两个位置
/etc/default/grub
/boot/grub2/grub.cfg
以前我都是简单粗暴的个性/boot/grub2/grub.cfg 现在发现并不合理
正确的方法是
修改/etc/default/grub
然后执行:
dracut --regenerate-all --force grub2-mkconfig -o /boot/grub2/grub.cfg reboot
编写命令行程序增加自动补全功能
最近正在编写一套完整的存储系统，涉及到命令行程序，需要增加自动补全功能以提高用户体验
这里用到了bash-completion工具可以直接yum装一下。
在/etc/bash_completion.d/ 目录下添加任意文件名文件，如flystor
比如你有如下命令树:
set
net
ip
dns
gw
option
hostname
date
即当打完set用双击tab 应该可以显示二层net option两个子命令，如输入为set net 双击tab则应该出现 ip dns gw的提示，并且所有命令都带有自动补全功能
对应flystor文件中的内容为：
function _sms()
{
local cur prev
COMPREPLY=()
cur="${COMP_WORDS[COMP_CWORD]}"
prev="${COMP_WORDS[COMP_CWORD-1]}"
case "${prev}" in
set)
COMPREPLY=( $(compgen -W "net option" ${cur}) )
return 0
;;
net)
COMPREPLY=( $(compgen -W "ip dns gw" ${cur}) )
return 0
;;
option)
COMPREPLY=( $(compgen -W "hostname date" ${cur}) )
return 0
;;
esac
}
代码初潜易懂，但这样写就很实用了。
完成后需要退出当前用户重新登录即可生效。
解决Mantis+SourceSVN插件，在Import everything无法完成
Mantis 免费是最大的优势而且功能并不比收费的弱多少。Mantis+SourceSVN基本就可以满足小型项目的BUG跟踪了。
这里安装Mantis和插件并不复杂，因为使用的是老式的SVN，因此插件选装的如下模块：
Source Control Integration 2.1.0
Source Subversion Integration 2.1.0
Source Subversion / WebSVN Integration 2.0.1
系统是Ubuntu 14.04 +nginx + php7-fpm
配置完成且点击import everything总是卡死。开始时以为是timeout不够长，但都没有能解决，只好从原码出发
最终定位到：
plugins/SourceSVN/SourceSVN.php
$t_svn_proc = proc_open( $t_svn_cmd, array( array( 'pipe', 'r' ), array( 'pipe', 'w' ), array( 'pipe', 'w' ) ), $t_pipes );
经过google大神的查找，发现此处的权限参数是有过争议的
参见：https://github.com/mantisbt-plugins/source-integration/issues/259
第二个w最初的时候是a，后为了适应windows而被改成了w
那么我们是不是可以试试原装参数呢？毕竟我们用的是linux
$t_svn_proc = proc_open( $t_svn_cmd, array( array( 'pipe', 'r' ), array( 'pipe', 'w' ), array( 'pipe', 'a' ) ), $t_pipes );
果然点击import everything很快就有反应了。
使用awk命令，并设定分割符为2个或以上的空格
因为要parse smbstatus的输出
117873 nobody nobody myhomepc (ipv4:192.168.199.2:62084) SMB3_02
因为myhompc (ipv4:192.168.199.2:62084) 归属于同一项machine, 如果简单用awk会将其分割为两列
如果-F 直接指定为’ ‘则会产生多个多余的列，因为前面nobody之间，有多个空格
因此我们的分割条件就变为了两个或以上的空格
本以为只能通过脚本来实现，结果一查发现awk竟然直接支持
awk -F '[[:space:]][[:space:]][[:space:]]*'
非交互式创建自签名证书
生成根证书的私钥，des3是加密算法，用其签发服务器端证书或者客户端证书，主要在于使用-passout pass:yourpassword 和-passinpass:yourpassword来指定密码
openssl genrsa -passout pass:4444 -des3 -out server.key 1024
生成服务器端签名请求证书（csr证书）
其中C是Country，ST是state，L是local，O是Organization，OU是Organization Unit，CN是common name
openssl req -new -passin pass:4444 -key server.key -out server.csr -subj /C=CN/ST=Shanghai/L=Shanghai/O=wyq/OU=wyq/CN=wyq.me/emailAddress=i@wyq.me
生成自签名证书，有效期设置为10年
cp server.key server.key.orig openssl rsa -in server.key.orig -out server.key -passin pass:4444 openssl x509 -req -days 3650 -in server.csr -signkey server.key -out server.crt
测试UDEV
使用udevadm test可以进行udev的测试
但其只接受udevadm info -q path -n /dev/sdb1 的输出作为参数
[root@node1 ~]# udevadm info -q path -n /dev/sdb1 /devices/pci0000:00/0000:00:10.0/host0/target0:0:1/0:0:1:0/block/sdb/sdb1 [root@node1 ~]# udevadm test --action=add /devices/pci0000:00/0000:00:10.0/host0/target0:0:1/0:0:1:0/block/sdb/sdb1 calling: test version 219 This program is for debugging only, it does not run any program specified by a RUN key. It may show incorrect results, because some values may be different, or not available at a simulation run. === trie on-disk === tool version: 219 file size: 7259752 bytes header size 80 bytes strings 1887992 bytes nodes 5371680 bytes Load module index Created link configuration context. timestamp of '/etc/udev/rules.d' changed Reading rules file: /usr/lib/udev/rules.d/10-dm.rules Reading rules file: /usr/lib/udev/rules.d/11-dm-lvm.rules Reading rules file: /usr/lib/udev/rules.d/13-dm-disk.rules Reading rules file: /usr/lib/udev/rules.d/40-redhat.rules Reading rules file: /usr/lib/udev/rules.d/42-usb-hid-pm.rules Reading rules file: /usr/lib/udev/rules.d/50-rbd.rules Reading rules file: /etc/udev/rules.d/50-sms.rules Reading rules file: /usr/lib/udev/rules.d/50-udev-default.rules Reading rules file: /usr/lib/udev/rules.d/60-alias-kmsg.rules Reading rules file: /usr/lib/udev/rules.d/60-cdrom_id.rules Reading rules file: /usr/lib/udev/rules.d/60-ceph-by-parttypeuuid.rules Reading rules file: /usr/lib/udev/rules.d/60-drm.rules Reading rules file: /usr/lib/udev/rules.d/60-keyboard.rules Reading rules file: /usr/lib/udev/rules.d/60-net.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-alsa.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-input.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-serial.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage-tape.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage.rules Reading rules file: /usr/lib/udev/rules.d/60-persistent-v4l.rules Reading rules file: /usr/lib/udev/rules.d/60-raw.rules Reading rules file: /etc/udev/rules.d/60-sms.rules Reading rules file: /usr/lib/udev/rules.d/61-accelerometer.rules Reading rules file: /usr/lib/udev/rules.d/63-md-raid-arrays.rules Reading rules file: /usr/lib/udev/rules.d/64-btrfs.rules Reading rules file: /usr/lib/udev/rules.d/65-md-incremental.rules Reading rules file: /usr/lib/udev/rules.d/69-dm-lvm-metad.rules Reading rules file: /usr/lib/udev/rules.d/70-mouse.rules Reading rules file: /etc/udev/rules.d/70-persistent-ipoib.rules Reading rules file: /usr/lib/udev/rules.d/70-power-switch.rules Reading rules file: /usr/lib/udev/rules.d/70-touchpad.rules Reading rules file: /usr/lib/udev/rules.d/70-uaccess.rules Reading rules file: /usr/lib/udev/rules.d/71-biosdevname.rules Reading rules file: /usr/lib/udev/rules.d/71-seat.rules Reading rules file: /usr/lib/udev/rules.d/73-idrac.rules Reading rules file: /usr/lib/udev/rules.d/73-seat-late.rules Reading rules file: /usr/lib/udev/rules.d/75-net-description.rules Reading rules file: /usr/lib/udev/rules.d/75-probe_mtd.rules Reading rules file: /usr/lib/udev/rules.d/75-tty-description.rules Reading rules file: /usr/lib/udev/rules.d/78-sound-card.rules Reading rules file: /usr/lib/udev/rules.d/80-drivers.rules Reading rules file: /usr/lib/udev/rules.d/80-net-name-slot.rules Reading rules file: /usr/lib/udev/rules.d/80-net-setup-link.rules Reading rules file: /usr/lib/udev/rules.d/81-kvm-rhel.rules Reading rules file: /usr/lib/udev/rules.d/84-nm-drivers.rules Reading rules file: /usr/lib/udev/rules.d/85-nm-unmanaged.rules Reading rules file: /usr/lib/udev/rules.d/90-alsa-tools-firmware.rules Reading rules file: /usr/lib/udev/rules.d/90-iprutils.rules Reading rules file: /usr/lib/udev/rules.d/90-vconsole.rules Reading rules file: /usr/lib/udev/rules.d/91-drm-modeset.rules Reading rules file: /usr/lib/udev/rules.d/95-ceph-osd.rules Reading rules file: /usr/lib/udev/rules.d/95-dm-notify.rules Reading rules file: /usr/lib/udev/rules.d/95-udev-late.rules Reading rules file: /usr/lib/udev/rules.d/98-kexec.rules Reading rules file: /usr/lib/udev/rules.d/98-rdma.rules Reading rules file: /usr/lib/udev/rules.d/99-systemd.rules rules contain 49152 bytes tokens (4096 * 12 bytes), 15467 bytes strings 2466 strings (32321 bytes), 1723 de-duplicated (17598 bytes), 744 trie nodes used GROUP 6 /usr/lib/udev/rules.d/50-udev-default.rules:52 IMPORT '/sbin/blkid -o udev -p /dev/sdb1' /usr/lib/udev/rules.d/60-ceph-by-parttypeuuid.rules:26 starting '/sbin/blkid -o udev -p /dev/sdb1' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_SCHEME=gpt' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_NAME=X0Hu3Mr1' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_UUID=a04af164-70cb-42b9-924b-6038ccec87ac' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_TYPE=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_NUMBER=1' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_OFFSET=32768' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_SIZE=4096000' '/sbin/blkid -o udev -p /dev/sdb1'(out) 'ID_PART_ENTRY_DISK=8:16' '/sbin/blkid -o udev -p /dev/sdb1' [3610] exit with return code 0 LINK 'disk/by-parttypeuuid/ebd0a0a2-b9e5-4433-87c0-68b6b72699c7.a04af164-70cb-42b9-924b-6038ccec87ac' /usr/lib/udev/rules.d/60-ceph-by-parttypeuuid.rules:29 LINK 'disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0-part1' /usr/lib/udev/rules.d/60-persistent-storage.rules:68 IMPORT builtin 'blkid' /usr/lib/udev/rules.d/60-persistent-storage.rules:82 probe /dev/sdb1 raid offset=0 LINK 'disk/by-partuuid/a04af164-70cb-42b9-924b-6038ccec87ac' /usr/lib/udev/rules.d/60-persistent-storage.rules:96 LINK 'disk/by-partlabel/X0Hu3Mr1' /usr/lib/udev/rules.d/60-persistent-storage.rules:97 RUN '/tmp/tt %k' /etc/udev/rules.d/60-sms.rules:1 handling device node '/dev/sdb1', devnum=b8:17, mode=0660, uid=0, gid=6 preserve permissions /dev/sdb1, 060660, uid=0, gid=6 preserve already existing symlink '/dev/block/8:17' to '../sdb1' found 'b8:17' claiming '/run/udev/links/\x2fdisk\x2fby-partlabel\x2fX0Hu3Mr1' creating link '/dev/disk/by-partlabel/X0Hu3Mr1' to '/dev/sdb1' preserve already existing symlink '/dev/disk/by-partlabel/X0Hu3Mr1' to '../../sdb1' found 'b8:17' claiming '/run/udev/links/\x2fdisk\x2fby-parttypeuuid\x2febd0a0a2-b9e5-4433-87c0-68b6b72699c7.a04af164-70cb-42b9-924b-6038ccec87ac' creating link '/dev/disk/by-parttypeuuid/ebd0a0a2-b9e5-4433-87c0-68b6b72699c7.a04af164-70cb-42b9-924b-6038ccec87ac' to '/dev/sdb1' preserve already existing symlink '/dev/disk/by-parttypeuuid/ebd0a0a2-b9e5-4433-87c0-68b6b72699c7.a04af164-70cb-42b9-924b-6038ccec87ac' to '../../sdb1' found 'b8:17' claiming '/run/udev/links/\x2fdisk\x2fby-partuuid\x2fa04af164-70cb-42b9-924b-6038ccec87ac' creating link '/dev/disk/by-partuuid/a04af164-70cb-42b9-924b-6038ccec87ac' to '/dev/sdb1' preserve already existing symlink '/dev/disk/by-partuuid/a04af164-70cb-42b9-924b-6038ccec87ac' to '../../sdb1' found 'b8:17' claiming '/run/udev/links/\x2fdisk\x2fby-path\x2fpci-0000:00:10.0-scsi-0:0:1:0-part1' creating link '/dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0-part1' to '/dev/sdb1' preserve already existing symlink '/dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0-part1' to '../../sdb1' created db file '/run/udev/data/b8:17' for '/devices/pci0000:00/0000:00:10.0/host0/target0:0:1/0:0:1:0/block/sdb/sdb1' .ID_FS_TYPE_NEW= ACTION=add DEVLINKS=/dev/disk/by-partlabel/X0Hu3Mr1 /dev/disk/by-parttypeuuid/ebd0a0a2-b9e5-4433-87c0-68b6b72699c7.a04af164-70cb-42b9-924b-6038ccec87ac /dev/disk/by-partuuid/a04af164-70cb-42b9-924b-6038ccec87ac /dev/disk/by-path/pci-0000:00:10.0-scsi-0:0:1:0-part1 DEVNAME=/dev/sdb1 DEVPATH=/devices/pci0000:00/0000:00:10.0/host0/target0:0:1/0:0:1:0/block/sdb/sdb1 DEVTYPE=partition ID_BUS=scsi ID_FS_TYPE= ID_MODEL=VMware_Virtual_S ID_MODEL_ENC=VMware\x20Virtual\x20S ID_PART_ENTRY_DISK=8:16 ID_PART_ENTRY_NAME=X0Hu3Mr1 ID_PART_ENTRY_NUMBER=1 ID_PART_ENTRY_OFFSET=32768 ID_PART_ENTRY_SCHEME=gpt ID_PART_ENTRY_SIZE=4096000 ID_PART_ENTRY_TYPE=ebd0a0a2-b9e5-4433-87c0-68b6b72699c7 ID_PART_ENTRY_UUID=a04af164-70cb-42b9-924b-6038ccec87ac ID_PART_TABLE_TYPE=gpt ID_PATH=pci-0000:00:10.0-scsi-0:0:1:0 ID_PATH_TAG=pci-0000_00_10_0-scsi-0_0_1_0 ID_REVISION=1.0 ID_SCSI=1 ID_TYPE=disk ID_VENDOR=VMware_ ID_VENDOR_ENC=VMware\x2c\x20 MAJOR=8 MINOR=17 SUBSYSTEM=block TAGS=:systemd: USEC_INITIALIZED=244571 run: '/tmp/tt sdb1' Unload module index Unloaded link configuration context.
对gluster进行dd操作，参数带oflag=direct时对于某些文件的性能特别差
测试时对gluster的volume进行dd(带oflag=direct)，有时会出现某些文件名的文件性能特别差。
gluster的弹性hash算法，决定了在使用非EC类型的卷时，文件是会随机落到某些盘上，不同文件名的文件所对应的subvolume不同，即所落的盘不一样。这就对磁盘的性能有一定的要求，当出现此现象时，一般可以总结为有坏盘，慢盘，或磁盘的write cache未打开。
通过dmesg |grep sdb来检测盘是否有打开wirte cache
如没有，可通过hdparm或sdparm来进行enable处理