A Technical I.T./DevOps Blog
Problem scenario
Your Python MR (mapreduce) job is failing. You do not know why.
You may or may not get an error like this: “Error: java.lang.RuntimeException: PipeMapRed.waitOutputThreads(): subprocess failed with code 1”
Other symptoms you may experience is the MapReduce job takes a great deal of time. It seems to hang. What should you do?
Solution
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Problem scenario
Linux SUSE won’t install. When the installation process is happening it stops with an abortive error that exits the pretty GUI menu sequence. You get “linuxrc 7.0.15 (Kernel 5.3.18-lp152.19-default) an error occurred during the installation.” What should you do to install SUSE?
Possible Solution #1
Start over. When you see this window “YaST2 The system has an active network connection.
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Problem scenario
You want to ensure you web application is protected from buffer overflows, injection attacks and other vulnerabilities that could reveal sensitive information. How do you harden a website application and follow security recommended practices?
Possible Solution #1
Endeavor to prevent injection attacks. Minify the website application by not allowing file uploads and limit POST requests to 2 MB (page 28 of Node.js Security by Liran Tal).
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Problem scenario
You have a multi-line variable in Python. You want to convert each line to be its own item in a list. How do you make a multi-line string variable to become a list with the same contents?
Solution
Use the .splitlines() method to manipulate the string in this way.
Here is an example:
list_of_input=”””a line here
another line there. …
Continue reading “Using Python How Do You Convert Each Line to Be an Item in a List?”
Problem scenario
You run a cargo command. You get this error:
error[E0658]: use of unstable library feature ‘str_strip’: newly added
–> /home/jdoe/.cargo/registry/src/github.com-1ecc6299db9ec823/ethbloom-0.10.0/src/lib.rs:69:1
|
69 | / construct_fixed_hash! {
70 | | /// Bloom hash type with 256 bytes (2048 bits) size.
71 | | pub struct Bloom(BLOOM_SIZE);
72 | | }
| |_^
|
= note: see issue #67302 https://github.com/rust-lang/rust/issues/67302 for more information
= note: this error originates in a macro (in Nightly builds,
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Problem scenario
Using a Debian/Ubuntu distribution of Linux, how do you install kubeadm, kubectl, and/or kubelet?
You want to install kubeadm, kubectl or kubelet (without retrieving the binary of the file from a website and do a regular installation). What do you do?
Solution
Here is another way to install kubectl, kubelet and kubeadm:
curl -s https://packages.cloud.google.com/apt/doc/apt-key.gpg | sudo apt-key add
sudo apt-add-repository “deb http://apt.kubernetes.io/ kubernetes-xenial main”
sudo apt-get -y install kubeadm kubelet kubectl
(If you can download a file from the internet and want to avoid using apt commands,
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Problem scenario
You are using a familiar application on a Mac. You cannot find a basic command button or menu option. What should you do?
Solution
At the very top of your screen, outside of the application itself, there is a ribbon. There should be drop down menu options specific for the application.
We find that some problems are caused because of time pressure.
…
Continue reading “How Do You Find the Menu Option, Button or Feature for an Application in MacOS?”
Problem scenario
Hadoop is not working correctly. You can get either a mapreduce job to work or a “hadoop” CLI command to work. But neither work unless you change an .XML file in between each operation.
Map Reduce jobs, when they are failing (and the Hadoop commands are working), there may be an error like this:
2021-01-01 22:47:42,337 INFO mapreduce.Job: Task Id : attempt_1609558624072_0001_m_000003_1,
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Problem scenario
You run a bundle command (e.g., bundle exec foobar create). It fails with an error such as “Could not find foobar in any of the sources”.
What should you do?
Solution
Remove the relevant Gemfile.lock file (e.g., in the directory you are running bundle) if you are allowed to. Are you using a variety of bundle commands? Each one could create a Gemfile.lock file so be aware of this.
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Problem scenario
In Python you try operations like these two:
5 ^ 6
9 ^ 10
Both return “3”. Why is this?
Solution
The exclusive or (aka XOR) symbol “^” “copies the bit if it is set in one operand but not both.” (Taken from https://www.tutorialspoint.com/python/python_basic_operators.htm)
Here are some integers with their binary representation one space away:
3 11
5 101
6 110
9 1001
10 1010
5 is represented as 101.
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