I/O error, dev fd0, sector 0

This happens in my Ubuntu VM and the log usually have these 2 messages

[  148.462686] blk_update_request: I/O error, dev fd0, sector 0
[  148.462735] floppy: error -5 while reading block 0

To get rid of those messages:

echo "blacklist floppy" | sudo tee /etc/modprobe.d/blacklist-floppy.conf

sudo rmmod floppy

sudo update-initramfs -u

After reboot, you can verify that floppy module (lsmod | grep floppy) no longer get loaded automatically and there is no such messages in the log anymore.

Ubuntu download deb packages without installing

To download without installaing, just use the following command

apt-get -d install package

Once done, you can go /var/cache/apt/archives to retrieve the packages you had downloaded.

How to print Gmail email without header information

First click on the printer button

Click cancel when prompted

Go to Developer Tools

Once you in Deveoper tools mode, you will notice there is a new pane below that show all the HTML code. Expand bodycontainer div class, when you mouse over the first table element, you will notice the section on top will be highlighted as well. This means that particular HTML code is the one that generated the highlighted section. Delete this table element.

And you will notice that Gmail header is no longer there.

Repeat these steps with other element such as

hr - to remove the seperator
first table element under maincontent div class - to remove message header
first and second tr element under message table - to remove sender and receipeint email.

After deleting the unwanted header information, you will get a clean message content. And you can proceed to print it.

How to test UDP port is responding

Using the following command will do the trick.

# nc -zuv 3 192.168.123.123 5140
Connection to 192.168.123.123 5140 port [udp/*] succeeded!

Linux Biscuit!

Docker 1.8 with td-agent 2.2.1 container

This is a quick guide on setting up td-agent container with Docker 1.8

1. Create a directory to store your dockerfile and td-agent config file. 

mkdir ~/td-agent-es && cd ~/td-agent-es

2. Create a dockerfile as shown below
FROM ubuntu:14.04 ENV DEBIAN_FRONTEND noninteractive RUN apt-get update &&\ apt-get install -y --force-yes libssl1.0.0 curl RUN curl https://packages.treasuredata.com/GPG-KEY-td-agent | apt-key add - # add treasure data repository to apt RUN echo "deb [arch=amd64] http://packages.treasuredata.com/2/ubuntu/trusty/ trusty contrib" > /etc/apt/sources.list.d/treasure-data.list RUN apt-get update &&\ apt-get install -y --force-yes td-agent RUN /usr/sbin/td-agent-gem install fluent-plugin-elasticsearch ADD td-agent.conf /etc/td-agent/td-agent.conf EXPOSE 24224 CMD ["td-agent"]
3. Create td-agent.conf file as shown below
## built-in TCP input ## @see http://docs.fluentd.org/articles/in_forward <source></source> type forward # match docker logs <match docker.=""> #type stdout type elasticsearch logstash_format true host "#{ENV['ES_PORT_9200_TCP_ADDR']}" port 9200 flush_interval 5s </match>
4. Build the docker image

docker build -t td-agent-es .

5. Start elasticsearch container. As you can see from the td-agent.conf, the td-agent container will link to this elasticsearch container. Please note that this setup is not using any persistent storage mapping. You can refer to this link for more information on how to setup that mapping.

docker run -d -p 9200:9200 -p 9300:9300 --name es elasticsearch

6. Start your td-agent container 

docker run -d -p 24224:24224 --link es:es --name td-agent td-agent-es

7. Launch a hello-world to see if td-agent is forwarding log to elasticsearch container. Please note that Docker 1.8 add fluentd as one of the logging-driver. So this command will not work if you are using Docker with older version

docker run --log-driver=fluentd --log-opt fluentd-address=[your-host-IP-address]:24224 hello-world

8. Use the following command to check if elasticsearch container is receiving log. You can check container ID or container name using docker ps -a

curl -XGET 'http://[your-host-IP-address]:9200/_all/_search?q=*'

Install jobber on CentOS 6.*

All the commands below are executed using root user

1. Install go and git if you not already do so

yum install go
yum install git

2. You need to specify workspace directory, this can be any path in your system. For this example, i use the following directory as the workspace - /home/amd/go
3. Set the $GOPATH to this workspace directory

export GOPATH=/home/amd/go

4. Change directory to your workspace directory and run the following command to get the jobber files.

go get github.com/dshearer/jobber

5. As git supplied by CentOS 6 is version 1.7.1 and it cannot handle gopkg.in in package properly. If this is not down, you will encounter hang problem during compilation process. So you need to manually get the yaml.v2 package.

git clone --branch v2 https://github.com/go-yaml/yaml $GOPATH/src/gopkg.in/yaml.v2

6. Compile jobber package

make -C src/github.com/dshearer/jobber

7. Before proceed to next step, install daemonized if not already do so.

yum install daemonize

8. Install jobber

make install -C src/github.com/dshearer/jobber

9. Running the following command and you can see jobber service is running.

service jobber status

10. To create a scheduled job, you need to create .jobber file under user home directory. jobber file are written in YAML format.

 ---
- name: DailyBackup
  cmd: backup daily
  time: 0 0 13
  onError: Stop
  notifyOnError: false
  notifyOnFailure: true

11. Once it is created, you need to load the job

 /usr/local/bin/jobber reload

12. You can check the log of the job using this command.

 /usr/local/bin/jobber log