add do180.org

Olaf Bohlen

2020-12-15 b4d6ba8b935c3073be725494bcc6aac78c342282

add do180.org

 do180.org

New file
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* ISO/OSI Reference Model

7 Application Layer    |  mysql-client           ^
6 Presentation Layer   |                         |
5 Session Layer        |                         |
4 Transport Layer      |  TCP 3306               |
3 Network Layer        |  IP 10.88.0.74          | 
2 Datalink Layer       |  ETH 0:14:4f:c9:85:70   |
1 Physical Layer       v  Copper/Fibre           |



* Container components

#+begin_src ditaa :file processlist-containers.png :cmdline -E -s 0.8

|
+- 1 systemd
|
+- 42 bash
|
+- 23 vim
|
|---------------+  namespace, chroot, SELinux, cgroups, Seccomp
+- 53 mysql5.5  |
|---------------+
|---------------+  namespace, chroot, SELinux, cgroups, Seccomp
+- 53 mysql5.8  |
|---------------+
|------------+     namespace, chroot, SELinux, cgroups, Seccomp
+- 74 apache |
|------------+
|
+- 122 bash


#+end_src

* UNIX Memory Seperation

#+begin_src ditaa :file userland.png :cmdline -E -s 0.8 

            +---------------------------------+       Process
Userland    | Proc1, Proc2, ...               |          |
            |                                 |          v
            |                                 |       System Call
            +-----SystemCalls-----------------+          |
            +---------------------------------+          v
Kernel      | Device Driver, Scheduler,       |       Kernel Driver
Space       | Memory Management, ...          |
            +---------------------------------+
#+end_src 

* docker vs podman components

                                 (root)
docker-cli ---REST (HTTP)---> docker-daemon ----> container
                               [webserver]

 (root)
podman   -> CRI-O -> runC -> container
            (Container Runtime Interface - OCI (Open Container Intiative))

alias docker=podman



* oc command line tool parameter

oc is a modified kubectl, but full compatible 

| Command | SubCommand  | Resource Type              | [<Resource Name>] |
|---------+-------------+----------------------------+-------------------|
| oc      | get         | pod                        | [name]            |
| kubectl | describe    | svc / service              |                   |
|         | edit        | all                        |                   |
|         | get -o yaml | replicationcontroller / rc |                   |
|         | get -o json | deploymentconfig / dc      |                   |
|         | delete      | buildconfig / bc           |                   |
|         | create      | imagestream / is           |                   |
|         |             | NetworkPolicy              |                   |

# oc new-project
# oc new-app
# oc rsh <podname>


* UNIX Kernel Memory 

#+begin_src ditaa :file system_memory.png :cmdline -E -s 0.8 

+--------------------------------+
|0Heap                           |
|                                |
|                                |
|                                |
|                                |
|                                |
+--------------------------------+
Gap
+--------------------------------+
|                                |
|                                |
|                                |
|Stack                       2^64|
+--------------------------------+

#+end_src