Kev's Development Toolbox

October 23, 2017February 12, 2018

All disks are not equal, especially cheap consumer disks without temperature sensors (a.k.a HP DL380 G7 fan speeds running like a 747 on take off)

I’ve recently been enjoying the freedom of a homelab, creating VMs on VMware ESXi and installing all-the-things. I’ve had my HP Proliant DL380 G7 for a couple of weeks now and already accumulated a number of VMs for investigating a collection of things:

3x CentOS7 VMs running a Kubernetes cluster with a master and 2 nodes
Ubuntu 16.04 running GitLab, Jenkins and SonarQube
Ubuntu 16.04 running MongoDB (related to some investigation into querying publicly available Big Data datasets)
CentOS 7 running Weblogic 10.3.6 (installing JDK7 on CentOS)
OpenIndiana for no particular reason, just to install and check it out. That’s the cool thing about being able to spin up VMs though, right?

Prior to my DL380 arriving, I was pondering what type of disks to put in, and in particular whether I used go with cheap consumer laptop hard disks, more expensive (e.g. WD Red NAS disks), or named-brand HP disks. I went with a pair of HGST 500GB disks to start with, and ran into an issue with the cooling fans spinning up like a 747 taking off. Googling for “dl380 disk fans” turns up many related posts, and it turns out that some non-HP drives in Proliant servers may not report their internal temperature correctly, resulting in the server thinking the drives are overheating, and cranking up the fans to compensate.

Here’s a couple of screenshots (from the iLO – Integrated Lights Out) showing the fans ramping up to near unbearable noise levels over about 5 minutes:

iLO reporting the drives overheating:

Only after a couple of mins, but still running faster than probably should be at idle:

Starting to ramp up:
Getting unbearable now:

If I’d spent some more time reading aound I would have found this excellent article detailing this issue, and more specifically drives known to work in the DL380 and drives known to have this issue. Turns out, most of the WD disks do work, so I replaced the HGST drives with 2 WD Black 750GB drives. Now the server at idle runs with the fans between 10-13% and is actually no louder than a regular desktop.

Back to creating some more VMs 🙂

October 22, 2017October 22, 2017

Installing Grafana on Ubuntu 16.06

Following the install instructions here:

Add the repo to /etc/apt/sources.list and install with apt-get:

deb https://packagecloud.io/grafana/stable/debian/ jessie main

Add key:

curl https://packagecloud.io/gpg.key | sudo apt-key add -

Update and install:

sudo apt-get update
sudo apt-get install grafana

Start up the server service:

sudo service grafana-server start

To start at boot:

sudo update-rc.d grafana-server defaults

Up!

October 21, 2017October 21, 2017

Configuring Gitlab installation

After installing GitLab, by default your project urls are @gitlab.example.com:

Your server domain is configured in the /etc/gitlab/gitlab.rb file, as described in the docs here.

To pick up your changes:

sudo gitlab-ctl reconfigure

October 21, 2017

Allowing user on CentOS to run docker command without sudo

Out of the box for a Docker install on CentOS 7, you have to sudo the docker command to interact with Docker. Per the post-install steps here, create a docker group and add your user to that group:

sudo groupadd docker

sudo usermod -aG docker youruser

Logging off and back on again, you should now be able to run the docker command without sudo.

On CentOS 7 this still didn’t work for me. Following this post, it appeared that docker.sock was owned by root and in the group root:

$ ls -l /var/run/docker.sock

srw-rw---- 1 root root 0 Oct 21 15:42 /var/run/docker.sock

Changing the group ownership:

$ sudo chown root:docker /var/run/docker.sock

$ ls -l /var/run/docker.sock

srw-rw---- 1 root docker 0 Oct 21 15:42 /var/run/docker.sock

After logging back on, now can run docker commands without sudo.