For volumes that have been restored from snapshots, use the dd or fio utilities to read from all of the blocks on a volume. All existing data on the volume will be preserved.
$ sudo dd if=/dev/xvdf of=/dev/xvdf conv=notrunc bs=1M
You can learn more about EBS volumes here.
Auto Scaling lifecycle hooks enable you to perform custom actions as Auto Scaling launches or terminates instances. For example, you could install or configure software on newly launched instances, or download log files from an instance before it terminates.
$ aws autoscaling put-lifecycle-hook —lifecycle-hook-name my-hook --auto-scaling-group-name my-asg --lifecycle-transition autoscaling:EC2_INSTANCE_LAUNCHING
$ aws autoscaling put-lifecycle-hook —lifecycle-hook-name my-hook --auto-scaling-group-name my-asg --lifecycle-transition autoscaling:EC2_INSTANCE_TERMINATING
$ aws autoscaling record-lifecycle-action-heartbeat --instance-id i-1a2b3c4d5e6f7g --lifecycle-hook-name my-launch-hook --auto-scaling-group-name my-asg
$ aws autoscaling complete-lifecycle-action —lifecycle-action-result CONTINUE —instance-id i-1a2b3c4d5e6f7g —lifecycle-hook-name my-hook —auto-scaling-group-name my-asg
$ aws autoscaling complete-lifecycle-action —lifecycle-action-result TERMINATE —instance-id i-1a2b3c4d5e6f7g —lifecycle-hook-name my-hook --auto-scaling-group-name my-asg
If you want to completely remove de device mapper multipath of your current Initial RAM Disk Image, you need to create a new initramfs than reboot your system using this new one.
# dracut -v -f --omit dm_multipath /boot/initramfs-$(uname -r).img $(uname -r)
This ansible role collects information about hardware and software from Linux servers, then inserts this information on a sqlite3 database.
The process happens in three phases.
I also included commands that collects information about EMC Storage, Veritas InfoScale and Cluster Server.
On ansible server.
yum install ansible sqlite3
On other servers.
yum install dmidecode
Install using ansible-galaxy.
mkdir -p /etc/ansible/roles && cd /etc/ansible/roles && ansible-galaxy install kdiegorsantos.hadouken
Create a group in your hosts ansible file named hadouken and fill with desired hosts.
cat <<EOF>> /etc/ansible/hosts
[hadouken]
webserver
dbserver
EOF
Change the default domain variable on defaults/main.yml.
cat <EOF> /etc/ansible/roles/hadouken/defaults/main.yml
domain: mydomain.com
EOF
Run this ansible role using the ansible-playbook command.
ansible-playbook /etc/ansible/roles/hadouken/role.yml
Run hadouken.py manually on a host.
/usr/local/sbin/hadouken.py
server_name: snelnxa72
server_release: Red Hat Enterprise Linux Server release 5.11 (Tikanga)
server_site: SNE
server_vendor: HP
server_model: ProLiant BL460c Gen8
server_serial: BRC2532JH4
server_cpu: Intel Xeon CPU E5-2650 2.00GHz / 2 Socket(s) / 32 CPU(s)/ 8 Core(s) per socket
server_memory: 32 GB
server_ip: 10.168.81.77
server_cluster: idem_cluster
server_clusternodes: snelnx187 snelnx189 snelnxa36 snelnxa68 snelnxa69 snelnxa70 snelnxa71 snelnxa72 snelnxa73
server_frame: 000290102907 000592600076 000595700007 000595700008 CKM00154803864
server_wwpn: 10006c3be5b076f1 10006c3be5b076f5
server_db: None
Display the content from the json file generated by hadouken.py.
cat /var/tmp/snenix002.json | python -m json.tool
{
"server_cluster": "",
"server_clusternodes": "",
"server_cpu": "2 Socket(s) Intel Xeon CPU E5540 @ 2.53GHz/ 16 CPU(s)/ 4 Core(s) per socket",
"server_db": "",
"server_frame": "",
"server_ip": "10.168.90.103",
"server_memory": "32 GB",
"server_model": "ProLiant BL460c G6",
"server_name": "snenix002",
"server_release": "Red Hat Enterprise Linux Server release 6.8 (Santiago)",
"server_serial": "BRC952N120",
"server_site": "SNE",
"server_vendor": "HP",
"server_wwpn": ""
}
Run sql commands in a easy way using query-db.sh, just give an argument to begin the search.
/etc/ansible/roles/hadouken/files/bin/query-db.sh BRC50966F0
server_id = 946
server_name = rjolnxc15
server_release = Red Hat Enterprise Linux Server release 6.5 (Santiago)
server_site = RJO
server_vendor = HP
server_model = ProLiant DL580 Gen8
server_serial = BRC50966F0
server_cpu = 4 Socket(s) Intel Xeon CPU E7-4890 v2 @ 2.80GHz/ 120 CPU(s)/ 15 Core(s) per socket
server_memory = 1292 GB
server_ip = 10.168.34.150
server_cluster =
server_clusternodes =
server_frame = 000595700042
server_wwpn = 5001438028cfc61c 5001438028cfc61e 5001438028cccf94 5001438028cccf96
server_db =
server_owner =
server_rack =
server_console =
last_update = 2016-09-23
Run sql commands using sqlite3.
sqlite3 -header -column /etc/ansible/roles/files/db/db.sqlite "select * from info where server_name = 'snelnxa72'"
server_id server_name server_release server_site server_vendor server_model server_serial server_cpu server_memory server_ip server_cluster server_clusternodes server_frame server_wwpn server_db server_owner server_rack server_console last_update
---------- ----------- ------------------------------------------------------ ----------- ------------- ------------------ ------------- --------------------------------------------------------------------------- ------------- ------------- -------------- ------------------- ------------ ----------- ---------- ------------ ----------- -------------- -----------
1 snenix002 Red Hat Enterprise Linux Server release 6.8 (Santiago) SNE HP ProLiant BL460c G6 BRC952N120 2 Socket(s) Intel Xeon CPU E5540 @ 2.53GHz/ 16 CPU(s)/ 4 Core(s) per socket 32 GB 10.168.90.103 2016-09-23
This project is licensed under the MIT license. See included LICENSE.md.
Here are some useful notes about network settings in RHEL7.
# hostnamectl set-hostname server001
# nmcli d
# nmcli c modify eth0 ipv4.addresses 192.168.0.30/24
# nmcli c modify eth0 ipv4.gateway 192.168.0.1
# nmcli c modify eth0 ipv4.dns 8.8.8.8
# nmcli c modify eth0 ipv4.method manual
# nmcli c down eth0 && nmcli c up eth0
# nmcli d show eth0
# ip addr show
# vi /etc/default/grub
# line 6: add GRUB_CMDLINE_LINUX="ipv6.disable=1 rd.lvm.lv=fedora-server/root.....
# grub2-mkconfig -o /boot/grub2/grub.cfg # systemctl reboot
# vi /etc/default/grub
# line 6: add GRUB_CMDLINE_LINUX="net.ifnames=0 rd.lvm.lv=fedora/swap rd.md=0.....
# grub2-mkconfig -o /boot/grub2/grub.cfg # systemctl reboot
Here are some useful notes about systemd.
# systemctl --version
# systemd-analyze
# systemd-analyze blame
# systemctl list-dependencies
# systemctl list-dependencies sshd.service
# journalctl
# journalctl /sbin/crond
# journalctl -b
# jornalctl --since=today
# journalctl -p err
# journalctl -f
# mkdir /var/log/jornald # echo "SystemMaxUse=50M" >> /etc/systemd/journald.conf # systemctl restart systemd-journald
# journalctl --disk-usage
# systemd-cgls
# systemd-cgtop
# systemctl kill httpd
# systemctl set-property httpd.service CPUShares=500
# systemctl show -p CPUShares httpd.service
# systemctl 'status|enable|disable|start|stop|restart|reload' sshd.service
# systemctl is-enabled sshd
# systemctl daemon-reload
# systemctl list-unit-files
# systemctl --failed
# systemctl -H root@jason.local status sshd.service
# systemctl show sshd
# localectl
# localectl set-locale LANG=en_US.utf8
# localectl set-keymap en_US
# localectl set-x11-keymap en_US
# timedatectl
# timedatectl set-time YYYY-MM-DD
# timedatectl set-time HH:MM:SS
# timedatectl list-timezones
# timedatectl set-timezone America/Sao_Paulo
# loginctl list-users
# loginctl list-sessions
# loginctl show-user kdiegorsantos
# systemctl set-default -f multi-user.target
# systemctl rescue
# systemctl isolate runlevel3.target
# systemctl isolate graphical.target
# systemctl 'poweroff|restart|suspend|hibernate'
OpenSSH 4.9+ includes a built-in chroot for sftp, but requires a few tweaks to the normal install.
You can create a rule to jail users and groups, it is very simple, if you want to create a rule based on group do the following.
# groupadd sftponly # gpasswd -a kdiegorsantos sftponly # cat <EOF> /etc/ssh/sshd_config
Subsystem sftp internal-sftp
Match Group sftponly # Match User kdiegorsantos
ChrootDirectory %h
ForceCommand internal-sftp
AllowTcpForwarding no
X11Forwarding no EOF
The chroot directory must be owned by root.
# chown root:root /home/kdiegorsantos # chmod 700 /home/kdiegorsantos
Change the user shell to prevent SSH login.
# usermod -s /bin/false kdiegorsantos
After change the SSH config file, make sure to reload the daemon to apply the rules.
# service sshd restart
Now only SFTP connections can be established by users on group sftponly.
[root@server002 ~]# ssh -l kdiegorsantos server001 kdiegorsantos@server001's password: This service allows sftp connections only. Connection to server001 closed. [root@server002 ~]#
If a user is able to write to the chroot directory then it is possible for them to escalate their privileges to root and escape the chroot. One way around this is to give the user two home directories – one “real” home they can write to, and one SFTP home that is locked down to keep sshd happy and your system secure. By using mount –bind you can make the real home directory appear as a subdirectory inside the SFTP home directory, allowing them full access to their real home directory.
# mkdir /home/chroot/kdiegorsantos # mount --bind /home/kdiegorsantos /home/chroot/kdiegorsantos # echo '/home/kdiegorsantos /home/chroot/kdiegorsantos none bind' >> /etc/fstab
If you are using Veritas InfoScale or Veritas Cluster Service in your environment, know that you can use the CLI to collect all useful information about your cluster.
The following commands is part of my shell script collect-exec.sh, make your changes to fit your needs.
# global collect directory.
collect_path=/var/tmp/collect_$(uname -n)_$(date +"%d%m%Y")
# check if HAD is running.
check_vcs_had=$(ps -ef | egrep -w "VRTSvcs/bin/had");
# if HAD is running export the right PATH
if [ ! -z "$check_vcs_had" ] ; then
export PATH=${PATH}:/opt/VRTSvcs/bin:/opt/VRTS/bin:/opt/VRTSsfmh/bin:/etc/vx/bin
fi
# Display every command to create this main.cf from begin.
hacf -verify /etc/VRTSvcs/conf/config/ -display > ${collect_path}/hacf_verify_display.txt
# Display the HAD version
had -version > ${collect_path}/had_version.txt
# Display all cluster users
hauser -display > ${collect_path}/hauser_display.txt
# List all cluster users
hauser -list > ${collect_path}/hauser_list.txt
# List all nodes in the cluster
hasys -list > ${collect_path}/hasys_list.txt
# Display the current state of all nodes in the cluster
hasys -state > ${collect_path}/hasys_state.txt
# Display the node number of all cluster nodes
hasys -nodeid > ${collect_path}/hasys_nodeid.txt
# Display the complete summary of the cluster
hastatus -summ > ${collect_path}/hastatus_summ.txt
# Display all clusters attributes
hatype -display > ${collect_path}/hatype_display.txt
# List all cluster attributes
hatype -list > ${collect_path}/hatype_list.txt
# List all resources in the cluster
hares -list > ${collect_path}/hares_list.txt
# Display all service groups in the cluster
hagrp -list > ${collect_path}/hares_list.txt
# Display the product version
haclus -value EngineVersion > ${collect_path}/haclus_engineversion.txt
# Display the cluster name
haclus -display > ${collect_path}/haclus_display.txt
# Display all imported disks in Storage Foundation
vxdisk list > ${collect_path}/vxdisk_list.txt
# Display all imported or exported disks in Storage Foundation
vxdisk -o alldgs list > ${collect_path}/vxdisk_o_alldgs_list.txt
# Display information about cluster file system
vxdctl -c mode > ${collect_path}/vxdctl_c_mode.txt
vxdctl mode > ${collect_path}/vxdctl_mode.txt
vxclustadm -v nodestate > ${collect_path}/vxclustadm_nodestate.txt
vxclustadm nidmap > ${collect_path}/vxclustadm_nidmap.txt
vxclustadm -v nodestate -d > ${collect_path}/vxclustadm_v_nodestate.txt
# Display information about GAB port membership
gabconfig -a > ${collect_path}/gabconfig_a.txt
gabconfig -W > ${collect_path}/gabconfig_W.txt
# Display the heartbeat links
lltstat > ${collect_path}/lltstat.txt
lltstat -nvv active > ${collect_path}/lltstat_active.txt
lltstat -n > ${collect_path}/lltstat_n.txt
lltconfig -W > ${collect_path}/lltconfig_W.txt
# Display information about cluster file system
cfscluster status > ${collect_path}/cfscluster_status.txt
# Display information about disk groups
vxdg list > ${collect_path}/vxdg_list.txt && vxdg free > ${collect_path}/vxdg_free.txt
# Display information about VxVM
vxprint -ht > ${collect_path}/vxprint_ht.txt
vxprint -Ath -q > ${collect_path}/vxprint_Athq.txt
vxprint -AGts > ${collect_path}/vxprint_AGts.txt
vxprint -m rootdg > ${collect_path}/vxprint_m_rootdg.txt
# Display information about fencing
vxfenadm -d > ${collect_path}/vxfenadm_d.txt
# Display information about VxDMP
vxdmpadm gettune all > ${collect_path}/vxdmpadm_gettune_all.txt
vxdmpadm listapm all > ${collect_path}/vxdmpadm_listapm_all.txt
vxdmpadm listenclosure all > ${collect_path}/vxdmpadm_listenclosure_all.txt
vxdmpadm stat restored > ${collect_path}/vxdmpadm_stat_restored.txt
vxdmpadm listctlr all > ${collect_path}/vxdmpadm_listctlr_all.txt
vxdmpdbprint > ${collect_path}/vxdmpdbprint.txt
vxddladm get namingscheme > ${collect_path}/vxddladm_namingscheme.txt
vxddladm listjbod > ${collect_path}/vxddladm_listjbod.txt
vxddladm listsupport > ${collect_path}/vxddladm_listsupport.txt
# Display the product license
vxlicense -p > ${collect_path}/vxlicense_p.txt
vxlicrep > ${collect_path}/vxlicrep.txt
vxlicrep -e > ${collect_path}/vxlicrep_e.txt
# Display all attributes from each resource
for a in $(/opt/VRTSvcs/bin/hares -list | awk '{print $1}') ; do
hares -display $a > ${collect_path}/hares_display.txt
done
# Display all attributes from each service group
for a in $(/opt/VRTSvcs/bin/hagrp -list | awk '{print $1}') ; do
hagrp -display $a > ${collect_path}/hagrp_display.txt
done
Setting up and deploying a FCoE (Fibre-channel over Ethernet) interface requires two packages in RHEL 6.2 or later.
# yum install -y fcoe-utils lldpad -y
# chkconfig lldpad on # chkconfig fcoe on
# cp /etc/fcoe/cfg-ethx /etc/fcoe/cfg-eth2 # cp /etc/fcoe/cfg-ethx /etc/fcoe/cfg-eth3
# sed -i 's/DCB_REQUIRED=\"yes\"/DCB_REQUIRED=\"no\"/g' /etc/fcoe/cfg-eth2 # sed -i 's/DCB_REQUIRED=\"yes\"/DCB_REQUIRED=\"no\"/g' /etc/fcoe/cfg-eth2
# service lldpad start # service fcoe start
# ifup eth2 # ifup eth3
# fcoeadm -i
If you need to create a new initrd (initial RAM Disk) in RHEL 3,4 or 4 don’t forget to make a backup of the current initrd before generate the new one.
# cp /boot/initrd-$(uname -r).img /boot/initrd-$(uname -r).img_$(date +"%d%m%Y")
# mkinitrd -f -v /boot/initrd-$(uname -r).img $(uname -r)
