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Easy SSH Login

March 30th, 2017 No comments

Here is a simple way to setup key (password-less) login on Unix-like systems.

Once you’ve configured SSH locally, add your public key to remote hosts using the following command:

ssh-copy-id remote_machine

After answering the password prompt, your public key will be appended to the remote ~/.ssh/authorized_keys2.

Remember to make sure the remote folder ~/.ssh is set to mode 0700 and ~/.ssh/authorized_keys2 to 0600, or auto login will be disabled.

 

Categories: Linux Tags: , , , , ,

Installing RancherOS and Rancher

March 5th, 2017 No comments

Install RancherOS

RancherOS installation docs are available at these links.

Docs are available here and here.

I found the docs a bit confusing so have included the steps I used here:

OS installation:

By default, any changes won’t persist and will be lost on reboot. The following steps explain how to install the OS on your hard disk:

Configure a new Linux 4.x compatible VM (>1.5G ram) and boot the memory based OS from CD. Get the most recent ISO release here.

When booted from CD, a shell for user rancher starts on the console. Unless your console allows cut/paste, you’ll want to set a password for user rancher to allow SSH login. SSH key howto.

$ sudo passwd rancher

Login using SSH ($ ssh [email protected])
. Note: this key will not survive a reboot, so in the following steps decline any offers to reboot.

Place your public SSH key in /home/rancher/cloud-config.yml using the following format:

#cloud-config.yml
hostname: myhost (optional)
ssh_authorized_keys:
– ssh-rsa AAAAB3NzaC1y…qKxUCAnBOcZ [email protected]
[there should be a couple of spaces at the beginning of the previous line, before the dash]

Format the drive where you want to install rancherOS. This command also labels the drive as required by Rancher. Ignore the rancher doc suggestion to reboot after this command.

$ sudo mkfs.ext4 -L RANCHER_STATE /dev/sda (may not be /dev/sda – with kvm, i use /dev/vda)

Now install RancherOS to disk, along with the SSH key you provided:


$ sudo ros install -c cloud-config.yml -d /dev/sda (again, change sda if necessary)

Reply Y to continue, and then Y to reboot.

If you need to change the hostname:

$ sudo ros config set hostname

Install Rancher Server and Agent

Rancher quick-start doc can be found here.

However Rancher Server is incredibly easy to install. This one liner will do the trick:

$ sudo docker run -d –restart=unless-stopped -p 8080:8080 rancher/server
(WordPress messes up <dash><dash>restart in the line above)

Once Rancher Server and its UI are up and running, you’ll need to install Rancher Agent on each Docker host (including RancherOS hosts). The Rancher UI explains the process clearly and makes it easy.

Categories: Docker, Linux Tags: , , , ,

Proxmox blacklisting IPMI hardware watchdog

August 22nd, 2016 No comments

My Proxmox 4.1 wouldn’t reboot. A quick look at the logs showed this was caused by the watchdog. My Supermicro (like HP) uses an IPMI hardware watchdog, but the Proxmox default is softdog.

In fact, by default, Proxmox disables loading of the ipmi_watchdog kernel module. And if you remove it from their blacklist, they just overwrite on the next update.

The fix is to uncomment the ipmi_watchdog line in /etc/default/pve-ha-manager, like so:

# select watchdog module (default is softdog)
WATCHDOG_MODULE=ipmi_watchdog

After you reboot, you should see ipmi_watchdog output by lsmod.

Categories: Linux Tags: , ,

ZFS pool not imported automatically in Proxmox 4.1 (and Jessie)

August 22nd, 2016 No comments
From zfsonlinux issue #4496:
btbroot commented on May 24 edited

Hello.

This is actually a grave bug. Currently (zfsutils 0.6.5.7-8-jessie), zfs-import-cache.service starts before systemd-remount-fs.service and fails to import pools because the / filesystem is mounted read-only at this stage. See the fix below.

--- /lib/systemd/system/zfs-mount.service-  2016-05-24 15:44:31.460000000 -0400
+++ /lib/systemd/system/zfs-mount.service   2016-05-24 16:08:56.156000000 -0400
@@ -8,7 +8,7 @@
 After=zfs-import-cache.service
 After=zfs-import-scan.service
 Before=local-fs.target
-Before=systemd-remount-fs.service
+After=systemd-remount-fs.service

 [Service]
 Type=oneshot

 

Categories: Linux Tags:

Script to Retrieve Window Product Key

August 8th, 2016 No comments

I don’t know why MS makes it so hard to retrieve your Windows product key.

Here’s a simple script to get the job done:

productkey.vbs

Categories: Windows Tags: