Linux Performance Analysis useful resources

• Linux Performance Analysis in 60,000 Milliseconds
• Thinking Methodically about Performance
• The USE Method

ERROR on ../../tmp/openshift-install--761813450/main.tf line 44, in resource "vsphereprivate_import_ova" "import":

 Problem:

..

DEBUG vsphere_tag_category.category: Creation complete after 0s [id=urn:vmomi:InventoryServiceCategory:f49160e4-a017-404f-9ecf-88b93e02f300:GLOBAL]
DEBUG vsphere_tag.tag: Creating...                 
DEBUG vsphere_tag.tag: Creation complete after 0s [id=urn:vmomi:InventoryServiceTag:75e6da39-1493-4760-a360-5708375c1e49:GLOBAL]
DEBUG vsphereprivate_import_ova.import: Creating...
ERROR                                              
ERROR Error: failed to find provided vSphere objects: failed to find a host in the cluster that contains the provided datastore
ERROR                                              
ERROR   on ../../tmp/openshift-install--761813450/main.tf line 44, in resource "vsphereprivate_import_ova" "import":
ERROR   44: resource "vsphereprivate_import_ova" "import" {
ERROR                                              
ERROR                                              
FATAL failed to fetch Cluster: failed to generate asset "Cluster": failed to create cluster: failed to apply Terraform: failed to complete the change

..

Root cause of the problem:

This issue was caused by trying to use a datastore that was not shared storage on a cluster with multiple hypervisors.

 

linux split files

 split -b 1G -d movie.mp4 movie.mp4_part

Bulma.io: the modern CSS framework that just works.

 Bulma is a free, open source framework that provides ready-to-use frontend components that you can easily combine to build responsive web interfaces.

 https://bulma.io/

Themes:

https://jenil.github.io/bulmaswatch/

libera.chat: new irc environment for opensource communities

In the past I was using Freenode IRC server for getting support from open-source communities. After freenode I saw that some important communities moved this environment. I want to share details with you.

Server address:
/server irc.libera.chat 6667


You can connect with an irc client. IRC client suggestion: hexchat

Stats:

CVE-2021-44228: Proof-of-Concept for Critical Apache Log4j Remote Code Execution Vulnerability Available (Log4Shell)

 Plugin:

https://www.tenable.com/plugins/nessus/155999

 POC - Blog post:

https://www.tenable.com/blog/cve-2021-44228-proof-of-concept-for-critical-apache-log4j-remote-code-execution-vulnerability

Log4Shell: RCE 0-day exploit found in log4j2, a popular Java logging package

Who is impacted?​

Many, many services are vulnerable to this exploit. Cloud services like Steam, Apple iCloud, and apps like Minecraft have already been found to be vulnerable.

https://www.lunasec.io/docs/blog/log4j-zero-day/

X-Force Report URL:

https://exchange.xforce.ibmcloud.com/collection/Log4Shell-Zero-Day-Targeting-Java-Package-4daa3df4f73a51590efced7fb90bc949

netmiko: Multi-vendor network device library for python

 github.com/ktbyers/netmiko Multi-vendor library to simplify CLI connections to network devices; can be helpful espacially for SOAR projects

Create bootable Windows 11 iso on Ubuntu 20.04

 ❯ sudo dd bs=4M if=/mnt/hgfs/Ddd/Win11_English_x64v1.iso of=/dev/sdc conv=fdatasync  status=progress

WARN[0000] Conmon at /usr/bin/conmon invalid: outdated conmon version

 Çözüm:

 yum update conmon -y

 

Red Hat: nmcli kullanım notları

 

Aşağıdaki testler Red Hat Enterprise Linux 8.2 üzerinde gerçekleştirilmiştir.

nmcli linux sistemler üzerinde NetworkManager servisi üzerinden ağ ayarlarını komut satırı kullanarak kontrol edebileceğiniz kullanabileceğiniz bir araçtır.

Aktif profili görüntüle:

#nmcli con show

Yeni bir profil tanımla:
Profil tanımlarken kullanabileceğiniz parametrelerden bazıları: con-name,ifname,type,ipv4.address,ipv4.gateway

#nmcli con add con-name lab ifname eth0 type ethernet ipv4.method manual ipv4.address 172.25.250.11/24 ipv4.gateway

Profil güncelle:
Profil güncellerken kullanabileceğiniz parametrelerden bazıları:
connection.autoconnect,ipv4.dns,+ipv4.addresses

#nmcli con mod lab ipv4.dns 4.2.2.4
#nmcli con mod lab connection.autoconnect
#nmcli con mod lab +ipv4.addresses 10.1.1.1/24

Kubernetes sınav hazırlık içerikleri

Kubernetes online sınav ve kurs içerikleri için aşağıdaki siteyi ziyaret edebilirsiniz. 

https://killer.sh

IBM Security Learning Academy eğitim içerikleri

IBM Security Learning Academy'de IBM güvenlik çözümleri ve bilgi güvenliği konsepti hakkında fayda sağlayabileceğiniz güncel, ücretsiz eğitim içerikleri bulabilirsiniz.

Özellikle QRadar Security Intelligence Platform, Guardium, IBM Security SOAR, Zero Trust başlıklı eğitimlere ve daha önce kaçırdığınız etkinlik içerikleri için Event Replays altındaki içeriklere mutlaka gözatmanızı öneririm

https://www.securitylearningacademy.com/local/navigator/

kafkaserver installation on Red Hat 8.4

 yum install java -y
wget https://ftp.itu.edu.tr/Mirror/Apache/kafka/2.8.0/kafka_2.13-2.8.0.tgz
mv kafka_2.13-2.8.0.tgz /opt/
cd /opt/
tar -zxf kafka_2.13-2.8.0.tgz
ln -s /opt/kafka_2.13-2.8.0 /opt/kafka
useradd kafka
chown -R kafka:kafka /opt/kafka*

Edit: /etc/systemd/system/zookeeper.service
[Unit]
Description=zookeeper
After=syslog.target network.target

[Service]
Type=simple

User=kafka
Group=kafka

ExecStart=/opt/kafka/bin/zookeeper-server-start.sh /opt/kafka/config/zookeeper.properties
ExecStop=/opt/kafka/bin/zookeeper-server-stop.sh

[Install]
WantedBy=multi-user.target

Edit: /etc/systemd/system/kafka.service
[Unit]
Description=Apache Kafka
Requires=zookeeper.service
After=zookeeper.service

[Service]
Type=simple

User=kafka
Group=kafka

ExecStart=/opt/kafka/bin/kafka-server-start.sh /opt/kafka/config/server.properties
ExecStop=/opt/kafka/bin/kafka-server-stop.sh

[Install]
WantedBy=multi-user.target




systemctl start zookeeper
systemctl start kafka

Edge Computing nedir?

Türkçe faydalı bir kaynak olmuş.

https://www.karel.com.tr/blog/edge-computing-nedir-cloud-computing-ve-fog-computingden-farki-nedir

Konu ile alakalı diğer faydalı bir kaynak (English):

Edge computing is a distributed computing paradigm that brings computation and data storage closer to the location where it is needed, to improve response times and save bandwidth.^[1]

https://en.wikipedia.org/wiki/Edge_computing