gnome-disks komutu

Giriş

Bu komutu ilk olarak burada gördüm.

/usr/local Dizini - Kaynak Kod İle Yapılan Kurulumlar

Giriş

/usr/local paket yöneticisi (package manager) uygulamalarda tarafından dikkate alınmaz.

/usr/local vs /opt

Paket yönetimine dahil olmadığı için kaynak kod derlenerek yapılan kurulumlar için kullanılabilir. Açıklaması şöyle. Kendi geliştirdiğimiz şeyleri de /usr/local/bin altına koyabiliriz.

Since these software projects are installed by extracting a .tar.gz file it sounds like they are self-contained applications and I would install them in /opt/<project>. Another common choice is /usr/local, but I prefer that for source based installs.

find komutu printf seçeneği

Specifier Olmayan Şeyler

Örnek

Boş dizinleri saymak için şöyle yaparızz

find . -maxdepth 1 -type d -empty -printf '\n' | wc -l

%h specifier - dirname
Örnek
*.c uzantılı dosyaların bulunduğu dizini yazdırmak için şöyle yaparız

find . -type f -iname '*.c' -printf '%h\0' |
  sort -z |
  uniq -zc |

%g specifier - group name
group bilgisini verir.

%s specifier - File's size in bytes
Örnek

Boyu en büyük dosyaları bulmak için şöyle yaparız

find . -mindepth 2 -printf "%s\t%p\n" | sort -n | cut -f 2- | tail -n $n

%p specifier - file's name

Örnek

Şöyle yaparız. %y ile d veya f karakteri dizin veya dosya olduğunu belirtir. %p ile dosya/dizin ismi gösterilir.

$ sudo find . -name 'example.com*' -printf "%y %p\n"
d ./archive/example.com
f ./renewal/example.com.conf
d ./live/example.com

%P specifier - Dosyanın Bulunduğu Dizin İsmi
Açıklaması şöyle. Yani en son dizinin ismini verir.

File's name with the name of the starting-point under which it was found removed.

Örnek

Şöyle yaparız

find /Volumes/SpeedyG -type d >> file.txt

# Çıktı şöyle
/Volumes/SpeedyG/folder1  
/Volumes/SpeedyG/folder2  
/Volumes/SpeedyG/folder2

find /Volumes/SpeedyG -type d -printf '%P\n' >> file.txt

# Çıktı şöyle
folder1  
folder2  
folder3

Örnek

Şöyle yaparız

$ find /usr/local/bin/ /bin/ -printf '%P\n'

%t - File's last modification time

Örnek ver

%u specifier - File's user name
user yani dosya sahibini (owner) verir. Şöyle yaparız.

$ sudo find /var -printf '%u:%g\n' | sort -t: -u
_apt:root
clamav:adm
clamav:clamav
colord:colord
daemon:daemon
lightdm:lightdm
lp:lp
man:root
speech-dispatcher:root
statd:nogroup
steeldriver:crontab
steeldriver:lightdm
steeldriver:steeldriver
syslog:adm
systemd-timesync:systemd-timesync
testuser:crontab





Kubernetes ve DNS

Giriş

Açıklaması şöyle

You can set up a DNS service for your Kubernetes cluster using an add-on.

We all know how DNS works in the case of the internet. Every website has a unique address a.k.a domain (for e.g. www.amazon.com). A similar approach is applied in the case of service discovery in Kubernetes. DNS server watches the Kubernetes for new services and creates a set of DNS records for each one. If DNS has been enabled throughout your cluster then all Pods should automatically be able to resolve services by their DNS name.

For instance, in our case, the DNS service and control plane (Kubernetes control panel) acting together create a DNS record of shoppingcart-service.dev-ns . Pods in the dev-ns the namespace should be able to find the service by doing a name lookup for shoppingcart-service

Kubernetes provides the concept of namespaces to segregate different concerns. For instances, you can have different namespaces for dev, test and prodenvironments.

Headless Service

Açıklaması şöyle

Luckily, Kubernetes allows clients to discover pod IPs through DNS lookups. Usually, when you perform a DNS lookup for a service, the DNS server returns a single IP — the service’s cluster IP. But if you tell Kubernetes you don’t need a cluster IP for your service (you do this by setting the clusterIP field to None in the service specification ), the DNS server will return the pod IPs instead of the single service IP. Instead of returning a single DNS A record, the DNS server will return multiple A records for the service, each pointing to the IP of an individual pod backing the service at that moment. Clients can therefore do a simple DNS A record lookup and get the IPs of all the pods that are part of the service. The client can then use that information to connect to one, many, or all of them.

Setting the clusterIP field in a service spec to None makes the service headless, as Kubernetes won’t assign it a cluster IP through which clients could connect to the pods backing it.

Örnek

Şöyle yaparız

apiVersion: v1
kind: Service
metadata:
  name: grpc-server-service
spec:
  clusterIP: None
  selector:
    app: grpc-server
  ports:
    - port: 80
      targetPort: 8001

Packaging And Deployment

fiGiriş

Bir tane java projesini Linux'a kurmak için izlenen yol şöyleydi

1. mypackaging.sh çalıştırılır

Bu dosya maven'ı çalıştırır. maven bir tane zip üretir.

mvn -s ... -P ... clean package -D...

1. maven package phase çalışırken "makeself" kullanılarak tüm properties + jar + makeself ile kullanılan startup_script dosyasını içeren bir foo_installer.sh üretilir

2. maven package phase çalışırken "maven-assembly-plugin" kullanılarak bir zip üretilir. Aslında bu adım isteğe bağlı, makeself zaten her şeyi zipliyor gibi de düşünülebilir.

makeself

Örnek kullanım şöyle

Here is an example, assuming the user has a package image stored in a /home/joe/mysoft, and he wants to generate a self-extracting package named mysoft.sh, which will launch the “setup” script initially stored in /home/joe/mysoft :

makeself.sh /home/joe/mysoft mysoft.sh "Joe's Nice Software Package" ./setup

setup.sh içindeki metodlar şöyle

install_component()
{
  mkdir -v $DEPLOYMENT_DIR/app/"$1"
  cp -v -r ./foo.jar $DEPLOYMENT_DIR/app/"$1"
  cp -v -r "$2" $DEPLOYMENT_DIR/app/"$1"
}

perform_installation()
{
  install_component AFolder a.properties
  install_component AFolder b.properties
  ...
}
print_usage()
{
  echo "..."
}

setup.sh çalışması şöyle

#Check if help is selected
if [ "$1" == '-h' ]
then
  print_usage
  exit 1
fi

if (($EUID)); then
  echo "Non-root user can not run"
  exit 1
fi

if [ -d $DEPLOYMENT_DIR ]
then
  echo "$DEPLOYMENT_DIR exists"
else
  echo "Creating folder " $DEPLOYMENT_DIR
  mkdir -p $DEPLOYMENT_DIR
fi

perform_installation

Firmware

Giriş

Firmware paketleri kernel ile dağıtılmaz. Açıklaması şöyle

Many hardware device manufacturers do not embed firmware into their devices, they require firmware to be loaded into the device by the operating system's driver.

Some other manufacturers embed an old version of the firmware but allow an updated version to be loaded by the driver - quite often the embedded version is ancient and/or buggy (and rarely, if ever, updated in the device itself because that might require changes to the manufacturing or testing process - this is generally a deliberate design decision. The rationale is that the embedded firmware version doesn't have to be good, it just has to resemble something that's minimally functional - updates can and should be loaded by the driver)

The firmware files almost always have a license which is incompatible with the GPL (or even no explicit or discernible license, just an implied "right to use" by being distributed with the device itself and the Windows driver it comes with) and thus can not be distributed with the kernel itself, and has to be distributed as a separate package.

Firmware için şu link takip ederiz

Firmware for the Linux kernel is distributed separately and has its own development tree.

https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/

Firmware kurmak için önce yine apt install ile driver kurulur

Örnek

Şöyle yaparızz

sudo apt install firmware-ralink

dmesg çıktısında şunu alırız. İlk iki satırda firmware'in yüklendiği görülebilir.

... ieee80211 phy0: rt2x00lib_request_firmware: Info - Loading firmware file 'rt2870.bin'
... ieee80211 phy0: rt2x00lib_request_firmware: Info - Firmware detected - version: 0.36
... wlan0: authenticate with 30:23:03:41:73:67
... wlan0: send auth to 30:23:03:41:73:67 (try 1/3)
... wlan0: authenticated
... wlan0: associate with 30:23:03:41:73:67 (try 1/3)
... wlan0: RX AssocResp from 30:23:03:41:73:67 (capab=0x411 status=0 aid=5)
... wlan0: associated
... IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready

run-parts komutu

Giriş

Çöken veya çalışmayan cron.daily işlerini elle tetiklemek için kullanılır. Örneğin günlük yedekleme (backup) çalışmadıysa.

Örnek

Şöyle yaparız

sudo run-parts /etc/cron.daily