A Technical I.T./DevOps Blog
Problem scenario
You want to use Python Eve to test it out. You also want to create a RESTful endpoint on an Ubuntu Linux server. How do you do this?
Solution
1. Install Eve on the Ubuntu server. Here is one way:
sudo apt-get -y update
sudo apt-get -y install python python-pip
sudo pip install eve
An alternative way to install it is given
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Continue reading “How Do You Use Python Eve as a RESTful Endpoint on an Ubuntu Server?”
Problem scenario
You are trying to install python-snappy on Ubuntu (or a Debian distribution of) Linux. You go here and find no obvious dependencies or prerequisites:
https://pypi.python.org/pypi/python-snappy
But when you try to install it, you run “python setup.py build” and get an error like this:
“/usr/lib/python2.7/distutils/dist.py:267: UserWarning: Unknown distribution option: ‘install_requires’
warnings.warn(msg)
running build
running build_py
package init file ‘__init__.py’ not found (or not a regular file)
package init file ‘__init__.py’ not found (or not a regular file)
running build_ext
building ‘_snappy’ extension
x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time – D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -I/usr/include/python2.7 -c
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Continue reading “How Do You Install python-snappy on an Ubuntu/Debian Linux Server?”
Problem scenario
You can connect the device with a network cable (in a wired fashion) to your network including the WiFi router’s physical ports. The wired connection works. You can connect other devices to the WiFi router wirelessly. You can even connect the IP-enabled device with the problem to other wireless routers. What is wrong?
Possible Solution #1
See if the incompatibility comes from the WiFi router having an access control list enabled.
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Problem scenario
You are not sure if snappy (the Python development tool) is installed. You try these two commands:
python
>>> import snappy
You see this:
“
Traceback (most recent call last):
File “<stdin>”, line 1, in <module>
File “snappy.py”, line 50, in <module>
from snappy_cffi import UncompressError, compress, decompress, \
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Problem scenario
You are trying to transfer a file named foobar.txt via FTP. But you get this error:
local: foobar.txt remote: foobar.txt
local: foobar.txt: Permission denied
What do you do with this “Permission denied” error?
Solution
The above error would not happen if the problem was on the remote server. (You would get “550 Failed to open file” if the problem was a lack of read permissions on the source of the FTP file transfer.)
Make sure that the destination of the FTP file transfer (that is the local directory) is one where your user has access to write to.
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Continue reading “What Do You Do When You Get “Permission Denied” in FTP?”
Problem scenario
You want to connect to your Raspberry Pi 3 with a Windows machine (e.g., Windows 7 or Windows 10 laptop). Both are on the same network. You want more than the command line interface. You want a desktop GUI connection beyond just a character prompt. What do you do?
Solution
On the Raspberry Pi do these three steps:
1.
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Problem scenario
You want to use Putty from a Windows 7 or Windows 10 workstation to connect to a Raspberry Pi 3 on the network. You want to connect via a command prompt (not with a GUI). What do you do?
Solution
On the Raspberry Pi do these three steps:
1. Change password for the pi user or create a new user.
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Problem scenario
You are running “sudo yum install foobar” but it is not working. You are trying to install a package on a RHEL server, but it is not available from the configured repositories. You notice that many packages you normally install are not available. What should you do?
Solution
Run this command:
sudo yum-config-manager –enable rhui-REGION-rhel-server-extras rhui-REGION-rhel-server-optional
FFR
To find the number of packages available to you in the configured repository (or repositories),
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Continue reading “How Do You Troubleshoot the Error “No package foobar available”?”
Problem scenario
You have some web servers that you want a new HAProxy server to distribute traffic to. You have an Ubuntu or Debian Linux server that you want HAProxy installed on. You want HAProxy to be a load balancer. What do you do?
Solution
Prerequisites
You have at least two web servers set up and you know their IP addresses (either internal or external).
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Continue reading “How Do You Set up HAProxy on a Linux Server?”
Problem scenario
You are trying to use subprocess and check_output in Python to run raw Bash/shell/Linux commands.
Your Python program has a line like this:
subprocess.check_output(“/usr/local/bin/coolprog arg1 /path/to/file.txt arg3”)
You get this error when you run the program:
File “/usr/lib/python2.7/subprocess.py”, line 566, in check_output
What do you do?
Solution
This solution only applies if the Bash command is constructed from known good input.
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