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Computer Notes/Kubernetes/Kubernetes Command-Line Cheat Sheet

Mflavell — Thu, 10 Sep 2026 00:14:12 GMT

Created page with "'''Kubernetes Command-Line Cheat Sheet''' is a reference guide for standard operations using the <code>kubectl</code> command-line interface to manage Kubernetes clusters, workloads, and node infrastructure. == Cluster Context & Namespaces == {| class="wikitable" ! Command !! Description |- | <code>kubectl config get-contexts</code> || List all available cluster contexts. |- | <code>kubectl config use-context <context-name></code> || Switch active cluster context...."

New page

'''Kubernetes Command-Line Cheat Sheet''' is a reference guide for standard operations using the <code>kubectl</code> command-line interface to manage Kubernetes clusters, workloads, and node infrastructure.

== Cluster Context & Namespaces ==
{| class="wikitable"
! Command !! Description
|-
| <code>kubectl config get-contexts</code> || List all available cluster contexts.
|-
| <code>kubectl config use-context <context-name></code> || Switch active cluster context.
|-
| <code>kubectl config set-context --current --namespace=<ns></code> || Set default namespace for current context.
|-
| <code>kubectl get ns</code> || List all namespaces in the cluster.
|}

== Viewing & Inspecting Resources ==
{| class="wikitable"
! Command !! Description
|-
| <code>kubectl get pods -A</code> || List all pods across all namespaces.
|-
| <code>kubectl get pods -o wide</code> || List pods with IP addresses and node assignments.
|-
| <code>kubectl get all -n <namespace></code> || Show all active resources in a specific namespace.
|-
| <code>kubectl describe <resource>/<name></code> || View detailed state, events, and configuration.
|-
| <code>kubectl get <resource> <name> -o yaml</code> || Export resource manifest to YAML format.
|}

== Deploying & Managing Workloads ==
{| class="wikitable"
! Command !! Description
|-
| <code>kubectl apply -f <file.yaml></code> || Create or update resources declaratively.
|-
| <code>kubectl delete -f <file.yaml></code> || Delete resources defined in a YAML manifest.
|-
| <code>kubectl scale deploy/<name> --replicas=<N></code> || Scale the replica count of a Deployment.
|-
| <code>kubectl rollout restart deploy/<name></code> || Perform a zero-downtime rolling restart.
|-
| <code>kubectl rollout undo deploy/<name></code> || Roll back to the previous deployment revision.
|}

== Debugging & Observability ==
{| class="wikitable"
! Command !! Description
|-
| <code>kubectl logs -f <pod-name></code> || Stream real-time logs from a pod container.
|-
| <code>kubectl logs -p <pod-name></code> || View logs from a previous crashed container instance.
|-
| <code>kubectl exec -it <pod-name> -- /bin/sh</code> || Open an interactive shell inside a running pod.
|-
| <code>kubectl port-forward svc/<name> 8080:80</code> || Forward local port 8080 to cluster service port 80.
|-
| <code>kubectl get events --sort-by='.metadata.creationTimestamp'</code> || List recent cluster events sorted by timestamp.
|-
| <code>kubectl top pods</code> / <code>kubectl top nodes</code> || Display live CPU and memory metrics.
|}

== Node Operations & Maintenance ==
{| class="wikitable"
! Command !! Description
|-
| <code>kubectl get nodes</code> || List all cluster nodes and their current status.
|-
| <code>kubectl cordon <node-name></code> || Mark a node as unschedulable.
|-
| <code>kubectl drain <node-name> --ignore-daemonsets</code> || Safely evict all pods before node maintenance.
|-
| <code>kubectl uncordon <node-name></code> || Mark a node as schedulable again.
|}

== Essential Productivity Shell Shortcuts ==
Add these shortcuts to your shell profile (<code>~/.bashrc</code> or <code>~/.zshrc</code>) to speed up workflow:

<syntaxhighlight lang="bash">
alias k='kubectl'
alias kgp='kubectl get pods'
alias kgs='kubectl get svc'
alias kgd='kubectl get deployments'
alias kdp='kubectl describe pod'
alias kl='kubectl logs -f'
</syntaxhighlight>

== See Also ==
* [[Kubernetes]]
* [[Secure Shell]]

[[Category:Kubernetes]]
[[Category:Cheat Sheets]]
[[Category:System Administration]]

Computer Notes/Kubernetes

Mflavell — Thu, 10 Sep 2026 00:13:56 GMT

← Older revision		Revision as of 00:13, 10 September 2026
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	[[Computer Notes/Kubernetes\|Kubernetes Command-Line Cheat Sheet]]		[[Computer Notes/Kubernetes/Kubernetes Command-Line Cheat Sheet\|Kubernetes Command-Line Cheat Sheet]]

Computer Notes/Kubernetes

Mflavell — Thu, 10 Sep 2026 00:13:25 GMT

Created page with "Kubernetes Command-Line Cheat Sheet"

New page

[[Computer Notes/Kubernetes|Kubernetes Command-Line Cheat Sheet]]

Computer Notes

Mflavell — Thu, 10 Sep 2026 00:12:52 GMT

← Older revision		Revision as of 00:12, 10 September 2026
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	[[Computer Notes/Security Services Platform\|Security Services Platform]]		[[Computer Notes/Security Services Platform\|Security Services Platform]]

			[[Computer Notes/Kubernetes\|Kubernetes]]

			[[Computer Notes/CA Siteminder\|CA Siteminder]]

	[[Computer Notes/CA Siteminder\|CA Siteminder]]		[[Computer Notes/CA Siteminder\|CA Siteminder]]

Computer Notes/Security Services Platform/Accessing the K8 Cluster

Mflavell — Thu, 10 Sep 2026 00:05:38 GMT

Step 1: Generate an SSH Key Pair on SSPI

Show changes

Computer Notes/Security Services Platform/Accessing the K8 Cluster

Mflavell — Thu, 10 Sep 2026 00:02:35 GMT

Created page with "'''SSH key pair authentication''' is a public-key cryptographic mechanism used within the Secure Shell (SSH) protocol to authenticate users or machines attempting to establish a remote network connection. Unlike traditional password-based authentication, key pair authentication relies on asymmetric cryptography, utilizing a mathematically linked pair of cryptographic keys: a '''public key''' and a '''private key'''. == Mechanism and Architecture == SSH key authenticatio..."

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'''SSH key pair authentication''' is a public-key cryptographic mechanism used within the Secure Shell (SSH) protocol to authenticate users or machines attempting to establish a remote network connection. Unlike traditional password-based authentication, key pair authentication relies on asymmetric cryptography, utilizing a mathematically linked pair of cryptographic keys: a '''public key''' and a '''private key'''.

== Mechanism and Architecture ==
SSH key authentication operates on a challenge-response model designed to verify identity without ever transmitting sensitive credential data over the network.

* '''Private Key:''' Kept strictly confidential on the client machine. It is protected by local file permissions (typically <code>chmod 600</code>) and can be further secured using a passphrase.
* '''Public Key:''' Placed on the target server, where it is stored in the remote user's configuration file (commonly <code>~/.ssh/authorized_keys</code>).

When a client requests an SSH session:
# The client sends a signal to the server identifying the public key it wishes to use for authentication.
# The server checks its <code>authorized_keys</code> file to confirm the key is authorized for the requested account.
# The server generates a cryptographic challenge (a random string of data) and sends it to the client.
# The client uses its local private key to sign the challenge, generating a digital signature, which is sent back to the server.
# The server uses the stored public key to verify the signature. If valid, the session is established.

== Common Algorithms and Key Generation ==
Key pairs are generated using software utilities such as OpenSSH's <code>ssh-keygen</code>. The security and performance of the key pair depend on the underlying mathematical algorithm:

* '''Ed25519:''' An Elliptic Curve Digital Signature Algorithm (EdDSA) scheme offering high performance, immunity to side-channel attacks, and a fixed key length of 256 bits. It is widely considered the modern standard.
* '''ECDSA:''' An elliptic curve implementation based on NIST curves. While secure, implementation flaws in random number generation can compromise private keys.
* '''RSA:''' A historical standard based on the integer factorization problem. Modern security guidelines mandate key lengths of 3072 or 4096 bits, as shorter lengths (e.g., 2048-bit) are increasingly vulnerable to advancing computational power.

== Advantages and Applications ==
SSH key pair authentication offers significant operational benefits over standard passwords:

* '''Mitigation of Brute-Force Attacks:''' Modern SSH keys possess high entropy, rendering dictionary and online brute-force attacks mathematically infeasible.
* '''Non-Interactive Automation:''' Keys facilitate secure, automated execution of administrative scripts, deployment pipelines (CI/CD), and infrastructure management tools without human intervention.
* '''Granular Access Control:''' System administrators can grant or revoke specific user access instantly by adding or removing individual public keys from a server, eliminating the need to reset global account passwords.

== See Also ==
* [[Secure Shell]]
* [[Public-key cryptography]]
* [[ssh-keygen]]

[[Category:Computer access control]]
[[Category:Network security]]

Computer Notes/Security Services Platform

Mflavell — Thu, 10 Sep 2026 00:02:20 GMT

← Older revision		Revision as of 00:02, 10 September 2026
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	[[Computer Notes]] > Security Services Platform		[[Computer Notes]] > Security Services Platform

			[[Computer Notes/Security Services Platform/Accessing the K8 Cluster\|Accessing the K8 Cluster]]

	= Overview =		= Overview =

Computer Notes/GIT/Git Cheat Sheet

Mflavell — Mon, 31 Aug 2026 17:08:52 GMT

Created page with "== Starting a Project == {| class="wikitable" |- ! Command !! Action |- | <code>git init</code> || Initialize a new local Git repository |- | <code>git clone <url></code> || Download a repository from a remote server |} == Staging & Committing == {| class="wikitable" |- ! Command !! Action |- | <code>git status</code> || Show modified, untracked, and staged files |- | <code>git add <file></code> || Stage a specific file |- | <code>git add .</code> || Stage a..."

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== Starting a Project ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git init</code> || Initialize a new local Git repository
|-
| <code>git clone <url></code> || Download a repository from a remote server
|}

== Staging & Committing ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git status</code> || Show modified, untracked, and staged files
|-
| <code>git add <file></code> || Stage a specific file
|-
| <code>git add .</code> || Stage all modified and new files
|-
| <code>git add -f <file></code> || Force-stage a file ignored by .gitignore
|-
| <code>git commit -m "message"</code> || Save staged snapshot with a description
|-
| <code>git commit -am "message"</code> || Stage tracked changes and commit in one step
|}

== Branching & Merging ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git branch</code> || List all local branches
|-
| <code>git branch <name></code> || Create a new branch
|-
| <code>git switch <name></code> || Switch to an existing branch
|-
| <code>git switch -c <name></code> || Create and switch to a new branch
|-
| <code>git merge <branch></code> || Merge target branch into active branch
|-
| <code>git branch -d <name></code> || Delete a merged branch
|}

== Syncing & Remotes ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git remote add origin <url></code> || Link local repository to a remote URL
|-
| <code>git fetch</code> || Download remote changes without merging
|-
| <code>git pull</code> || Fetch and merge changes from remote repository
|-
| <code>git push -u origin <branch></code> || Upload commits and set default remote branch
|-
| <code>git push</code> || Upload commits to linked remote branch
|}

== Viewing History & Files ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git log --oneline</code> || View condensed commit history
|-
| <code>git diff</code> || Show changes made to unstaged files
|-
| <code>git diff --staged</code> || Show changes staged for the next commit
|-
| <code>git ls-files</code> || List all files currently tracked by Git
|}

== Undoing Changes ==
{| class="wikitable"
|-
! Command !! Action
|-
| <code>git restore <file></code> || Discard uncommitted changes in a file
|-
| <code>git restore --staged <file></code> || Unstage a file without losing changes
|-
| <code>git reset HEAD~1</code> || Undo last commit, keeping changes locally
|-
| <code>git reset --hard HEAD~1</code> || Permanently discard last commit and all work
|-
| <code>git commit --amend</code> || Add staged changes to or edit the last commit
|}

Computer Notes/GIT

Mflavell — Mon, 31 Aug 2026 17:08:33 GMT

← Older revision		Revision as of 17:08, 31 August 2026
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	git clone git@github.com:username/private-repo.git		git clone git@github.com:username/private-repo.git


			= The git process =

			** Clone the repo

			** Add / Modify files > git add (add the files you want to submit)

			** git status (Double check list)

			** git commit (saves locally)

			** git push (upload changes)


			= Useful commands =

			====Add the a folder to git====

			git add '''path'''


			====Remove something that is staged====

			git restore --staged '''path'''


			====Check what is staged====

			git status


			====Commit the changes====

			git commit -m “Message for commit”

			or to amend a commit

			git commit –amend -m “Message for commit”

			====Uploading changes====

			git push


			[[Computer Notes/GIT/Git Cheat Sheet\|Git Cheat Sheet]]

Computer Notes/Python/Python Interview Cheat Sheet

Mflavell — Tue, 18 Aug 2026 01:41:48 GMT

Created page with " = High-Yield Python Patterns for Technical Interviews = == 1. Array (List) Iteration == Forget standard while loops or range(len(arr)) unless you specifically only need the index. Python has built-in ways to make this much cleaner and less prone to off-by-one errors. === The Enumerate Pattern (Crucial) === Whenever you need both the index and the value, always use enumerate. It shows operational maturity. nums = [10, 20, 30] for i, num in enumerate(nums): print(f"Ind..."

New page

= High-Yield Python Patterns for Technical Interviews =

== 1. Array (List) Iteration ==
Forget standard while loops or range(len(arr)) unless you specifically only need the index. Python has built-in ways to make this much cleaner and less prone to off-by-one errors.

=== The Enumerate Pattern (Crucial) ===
Whenever you need both the index and the value, always use enumerate. It shows operational maturity.

nums = [10, 20, 30]
for i, num in enumerate(nums):
print(f"Index: {i}, Value: {num}")

=== List Comprehensions ===
Use these for filtering or transforming data quickly. It saves space and looks highly professional.

# Create a list of squares for even numbers only

nums = [1, 2, 3, 4, 5]
evens_squared = [x2 for x in nums if x % 2 == 0]

=== Two-Pointer Setup ===
Very common for array manipulation and palindrome checks.

left, right = 0, len(nums) - 1
while left < right:
# Do logic, then converge
left += 1
right -= 1

== 2. String Manipulation ==
Remember: '''Strings in Python are immutable.''' You cannot do s[0] = 'a'. You must build a new string or convert it to a list of characters first.

=== Splitting and Joining ===
This is bread-and-butter for parsing messy log files or URIs.

# Splitting a messy log line

log = "ERROR User login failed"
parts = log.split() # Splits by any whitespace, stripping extras

# Rebuilding a string from a list

chars = ['G', 'o', 'o', 'g', 'l', 'e']
word = "".join(chars)

=== Reversing a String ===
Do not write a loop to reverse a string unless explicitly asked to. Use slicing.

s = "security"
reversed_s = s[::-1] # "ytiruces"

=== Character Math (ASCII) ===
Crucial for encryption/decryption basics or mapping characters to an array index.

# Convert char to ASCII int, and vice versa

val = ord('a') # 97
char = chr(97) # 'a'

# Map 'a'-'z' to 0-25

index = ord('c') - ord('a') # 2

== 3. Linked Lists ==
You will almost always have to write the boilerplate class yourself if the platform doesn't provide it. Memorize this exact structure.

=== The Node Class ===

class ListNode:
def **init**(self, val=0, next=None):
self.val = val
self.next = next

=== The "Dummy Node" Pattern ===
When doing Linked List insertions or deletions, always use a dummy node pointing to the head. It eliminates 90% of the edge cases regarding empty lists or modifying the very first node.

def process_list(head):
dummy = ListNode(0)
dummy.next = head
curr = dummy

```
while curr.next:
if curr.next.val == "target":
# Skip the node (Deletion)
curr.next = curr.next.next
else:
curr = curr.next

return dummy.next # Returns the real, potentially modified head

```

== 4. The "No-IDE" Cheat Codes (Collections) ==
Google interviewers expect you to use Python's standard library. Import these at the top of the file; it prevents you from reinventing the wheel.

=== Counters (Frequency Maps) ===

from collections import Counter

# Instantly counts occurrences

freq = Counter(['apple', 'apple', 'orange'])

# freq = {'apple': 2, 'orange': 1}

# Get top N most frequent items (great for finding IP log spammers)

top_two = freq.most_common(2)

=== DefaultDict ===
Saves you from writing if key not in my_dict: my_dict[key] = [] a hundred times.

from collections import defaultdict

# Automatically initializes missing keys with an empty list

adj_list = defaultdict(list)
adj_list['node_A'].append('node_B')

=== Deque (Double-Ended Queue) ===
If you need to pop from the left side of a list (queue.pop(0)), it takes $O(n)$ time and is a major red flag. Use a deque for $O(1)$ appends and pops on both ends.

from collections import deque
queue = deque([1, 2, 3])
queue.append(4) # Adds to right
queue.popleft() # Removes from left in O(1) time

== 5. Sorting and Lambdas (NEW) ==
In security engineering loops, you are frequently asked to sort complex data structures (e.g., sorting logs by timestamp, or users by privilege level).

=== Custom Sort Keys ===
Use lambda functions to sort tuples or dictionaries easily.

logs = [("10.0.0.1", 500), ("192.168.1.1", 200), ("10.0.0.2", 403)]

# Sort by the second item in the tuple (the HTTP status code)

logs.sort(key=lambda x: x[1])

# Sort in reverse (descending)

logs.sort(key=lambda x: x[1], reverse=True)

== 6. Graph & Tree Representation (NEW) ==
Security architecture heavily relies on trees (directory structures, IAM permissions) and graphs (network topologies, lateral movement).

=== Adjacency List for Graphs ===
The standard way to represent a network. Combine this with the deque for a flawless Breadth-First Search (BFS).

from collections import defaultdict, deque

# Build the graph

edges = [("A", "B"), ("A", "C"), ("B", "D")]
graph = defaultdict(list)
for u, v in edges:
graph[u].append(v)
graph[v].append(u) # Omit this line if the graph is directed

# Standard BFS Traversal

def bfs(start_node):
visited = set([start_node])
queue = deque([start_node])

```
while queue:
node = queue.popleft()
print(f"Processing {node}")

for neighbor in graph[node]:
if neighbor not in visited:
visited.add(neighbor)
queue.append(neighbor)

```

== 7. Critical Python Gotchas (NEW) ==
Avoid these traps on a whiteboard; interviewers specifically watch for them.

=== The Mutable Default Argument Trap ===
Never use a list or dictionary as a default argument in a function. It evaluates once at definition time, meaning subsequent calls will share the same list memory.

# BAD:

def add_to_list(val, my_list=[]):
my_list.append(val)
return my_list

# GOOD:

def add_to_list(val, my_list=None):
if my_list is None:
my_list = []
my_list.append(val)
return my_list

=== Initializing Min/Max Values ===
When you need to find a minimum or maximum value by iterating, do not initialize your tracker to 0 or 999999. Use Python's built-in infinity.

max_val = float('-inf')
min_val = float('inf')

Computer Notes/Python

Mflavell — Tue, 18 Aug 2026 01:39:46 GMT

← Older revision		Revision as of 01:39, 18 August 2026
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	[[Computer Notes/Python/PIP\|PIP]]		[[Computer Notes/Python/PIP\|PIP]]

			[[Computer Notes/Python/Python Interview Cheat Sheet\|Python Interview Cheat Sheet]]

← Older revision		Revision as of 00:12, 10 September 2026
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	[[Computer Notes/Security Services Platform\|Security Services Platform]]		[[Computer Notes/Security Services Platform\|Security Services Platform]]

			[[Computer Notes/Kubernetes\|Kubernetes]]

			[[Computer Notes/CA Siteminder\|CA Siteminder]]

	[[Computer Notes/CA Siteminder\|CA Siteminder]]		[[Computer Notes/CA Siteminder\|CA Siteminder]]