some more improvements to comments

Signed-off-by: Arnaud Morin <arnaud.morin@ovhcloud.com>

.gitignore

@@ -0,0 +1,41 @@
+#.gitignore
+#ex3/*.terraform*
+#ex3/terraform*
+
+# Local .terraform directories
+**/.terraform*
+
+# .tfstate files
+*.tfstate
+*.tfstate.*
+
+# Crash log files
+crash.log
+crash.*.log
+
+# Exclude all .tfvars files, which are likely to contain sensitive data, such as
+# password, private keys, and other secrets. These should not be part of version 
+# control as they are data points which are potentially sensitive and subject 
+# to change depending on the environment.
+*.tfvars
+*.tfvars.json
+
+# Ignore override files as they are usually used to override resources locally and so
+# are not checked in
+override.tf
+override.tf.json
+*_override.tf
+*_override.tf.json
+
+# Ignore transient lock info files created by terraform apply
+.terraform.tfstate.lock.info
+
+# Include override files you do wish to add to version control using negated pattern
+# !example_override.tf
+
+# Include tfplan files to ignore the plan output of command: terraform plan -out=tfplan
+# example: *tfplan*
+
+# Ignore CLI configuration files
+.terraformrc
+terraform.rc

README.md

@@ -1 +1,173 @@
-# merge-vs-rebase
+# Intro
+
+We created this set of exercises to give you the opportunity to express yourself technically. Do as much as you can in
+the time you have. Feel free to ask us questions, if any. No worries if you can't make it all by lack of time or
+understanding of what we're asking. We'll defrief it with you during our next call.
+
+**Have fun!**
+
+## Fork
+
+Register an account and fork this repo.
+
+You will push your results to your fork.
+
+# Ex. 1 - python
+
+This exercise will be split into multiple smaller ones. For each one
+you can create files named `a.py`, `b.py` and `c.py`. You maybe resuse the same
+environment for all sub-exercises
+
+Guidelines:
+- Use python version python3.7+.
+- Unless specified otherwise you can only use builtin modules.
+
+### python - A
+
+Write a script that prints out whatever text input is passed as argument
+
+Example:
+
+```
+$ python a.py ping ping ping
+ping ping ping
+```
+
+### python - B
+
+Write a script take takes one argument (-t/--target) which can only
+accept the following values `titi`, `toto`, `tata`. When called with a valid
+target, the script should print out the target text to stdout (`titi`, `toto` or `tata`).
+When an invalid target is provided an error message should be printed to stderr
+
+Example:
+
+```
+$ python b.py --target titi
+titi
+
+$ python b.py -t tutu
+usage: b.py [-h] [-t {titi,toto,tata}]
+b.py: error: argument -t/--target: invalid choice: 'tutu' (choose from 'titi', 'toto', 'tata')
+```
+
+### python - C
+
+Write a script that creates ascii art equivalent of text passed as argument.
+For this exercise you may use a 3rd party module.
+
+Example:
+
+```bash
+$ python c.py 'Hello buddies'
+ _   _        _  _          _                 _      _  _
+| | | |  ___ | || |  ___   | |__   _   _   __| |  __| |(_)  ___  ___
+| |_| | / _ \| || | / _ \  | '_ \ | | | | / _` | / _` || | / _ \/ __|
+|  _  ||  __/| || || (_) | | |_) || |_| || (_| || (_| || ||  __/\__ \
+|_| |_| \___||_||_| \___/  |_.__/  \__,_| \__,_| \__,_||_| \___||___/
+
+```
+
+# Ex. 2 - docker
+
+In ex2 folder, you will find a `app` binary.
+
+Can you build very lighweight docker image that contains ONLY `app` binary, and that execute `app` by default?
+
+Push your Dockerfile in the ex2 folder.
+
+# Ex. 3 - terraform
+
+In ex3 folder, you will find an incomplete `openrc` file.
+
+You will need to amend the file to configure the correct `OS_USERNAME`, `OS_PASSWORD` and `OS_REGION_NAME` with the one that we gave to you.
+
+Then, using `terraform`, can you write a plan to boot a `d2-4` with a floating IP.
+
+Bonus, on that instance, make sure a web server (`nginx`) is running.
+
+Push your `main.tf` file in ex3 folder.
+
+# Ex. 4 - git
+
+In this repo, there are two branches:
+
+- stein
+- queens
+
+Stein contains the following commits:
+
+- 1ff2641 (stein) G
+- cf24853 F
+- 3fcdfa0 E
+- cb8c71a D
+- 849ef26 C
+- 372c155 B
+- edc8ed7 A
+
+Queens contains the following commits:
+
+- 2624c16 (queens) F
+- 5e3521b B
+- edc8ed7 A
+
+So the common ancestor is A (same commit ID).
+
+B has been cherry-picked from stein to queens, without conflicts.
+
+F has also been cherry-picked but with conflicts (solved, of course).
+
+## Exercice
+
+You will need to create two branches:
+
+- merged
+- rebased
+
+### Merged
+
+Create the merged branch first:
+
+```bash
+git checkout -b merged origin/queens
+```
+
+Then merge the stein branch into your branch
+
+```bash
+git merge origin/stein
+```
+
+You will have a conflict to solved.
+
+Solve it, then push your `merged` branch to your repo.
+
+### Rebased
+
+Now create the rebased branch:
+
+```bash
+git checkout -b rebased origin/queens
+```
+
+Now rebase it on top of stein:
+
+```bash
+git rebase -i origin/stein
+```
+
+You will have a conflict to solved.
+
+Solve it, then push your `rebased` branch to your repo.
+
+## Check diff
+
+Now check the diff between your two branches `merged` and `rebased`.
+
+```bash
+git diff merged..rebased
+```
+
+Can you explain why you have a diff?
+
+Write down the explanation in ex4 folder (like in a `README.md` file)

ex1/a.py

@@ -0,0 +1,4 @@
+import sys
+
+argv = " ".join(sys.argv[1:])
+print("You've written:", argv)

ex1/b.py

@@ -0,0 +1,24 @@
+import argparse
+import sys
+
+vars = {"toto", "tata", "titi"}
+
+parser = argparse.ArgumentParser()
+
+parser.add_argument(
+    '-t', '--target',
+    nargs='+',
+    choices=vars,
+    help="Specify from 1 to 3 values from: toto, tata, titi.",
+    required=True
+)
+
+# Execute parsing
+args = parser.parse_args()
+
+# Check if arguments are more than expected
+if len(args.target) > 3:
+    print("Error: can be used **at max 3** values from 'toto', 'tata' and 'titi'.", file=sys.stderr)
+    sys.exit(1)
+
+print("You've written:", args.target)

ex1/c.py

@@ -0,0 +1,11 @@
+import sys
+import pyfiglet
+
+# check if executed without text and print help
+if len(sys.argv) < 2:
+    print("Usage: python c.py 'text to be converted'")
+    sys.exit(1)
+
+text = " ".join(sys.argv[1:])
+f = pyfiglet.figlet_format(text)
+print(f)

ex2/dockerfile

@@ -0,0 +1,3 @@
+FROM alpine:latest
+COPY app /app
+ENTRYPOINT ["/app"]

ex3/main.tf

@@ -0,0 +1,31 @@
+terraform {
+required_version = ">= 0.14.0"
+  required_providers {
+    openstack = {
+      source  = "terraform-provider-openstack/openstack"
+      version = "~> 1.53.0"
+    }
+  }
+}
+
+resource "openstack_networking_floatingip_v2" "_3245829148481055-FIP" {
+  pool = "Ext-Net"
+}
+
+resource "openstack_compute_instance_v2" "_3245829148481055-pci-test-ex3" {
+  name            = "_3245829148481055-pci-test-ex3"
+  image_id        = "d2083aa0-94ee-491d-a20c-0c8db1acdb96"
+  flavor_name     = "d2-4"
+  key_pair        = "3245829148481055-KP"
+  security_groups = ["default"]
+  user_data       = "#cloud-config\npackages:\n  - nginx\nruncmd:\n  - systemctl enable nginx\n  - systemctl start nginx"
+
+  network {
+    name = "3245829148481055-int-net"
+  }
+}
+
+resource "openstack_compute_floatingip_associate_v2" "_3245829148481055-FIP" {
+  floating_ip = "${openstack_networking_floatingip_v2._3245829148481055-FIP.address}"
+  instance_id = "${openstack_compute_instance_v2._3245829148481055-pci-test-ex3.id}"
+}

libvirt.pp

@@ -1,308 +0,0 @@
-# == Class: nova::compute::libvirt
-#
-# Install and manage nova-compute guests managed
-# by libvirt
-#
-# === Parameters:
-#
-# [*ensure_package*]
-#   (optional) The state of nova packages
-#   Defaults to 'present'
-#
-# [*libvirt_virt_type*]
-#   (optional) Libvirt domain type. Options are: kvm, lxc, qemu, uml, xen
-#   Defaults to 'kvm'
-#
-# [*vncserver_listen*]
-#   (optional) IP address on which instance vncservers should listen
-#   Defaults to '127.0.0.1'
-#
-# [*migration_support*]
-#   (optional) Whether to support virtual machine migration
-#   Defaults to false
-#
-# [*libvirt_cpu_mode*]
-#   (optional) The libvirt CPU mode to configure.  Possible values
-#   include custom, host-model, none, host-passthrough.
-#   Defaults to 'host-model' if libvirt_virt_type is set to kvm,
-#   otherwise defaults to 'none'.
-#
-# [*libvirt_cpu_model*]
-#   (optional) The named libvirt CPU model (see names listed in
-#   /usr/share/libvirt/cpu_map.xml). Only has effect if
-#   cpu_mode="custom" and virt_type="kvm|qemu".
-#   Defaults to undef
-#
-# [*libvirt_cpu_model_extra_flags*]
-#   (optional) This allows specifying granular CPU feature flags when
-#   specifying CPU models. Only valid, if cpu_mode and cpu_model
-#   attributes are specified and only if cpu_mode="custom".
-#   Defaults to undef
-#
-# [*libvirt_snapshot_image_format*]
-#   (optional) Format to save snapshots to. Some filesystems
-#   have a preference and only operate on raw or qcow2
-#   Defaults to $::os_service_default
-#
-# [*libvirt_disk_cachemodes*]
-#   (optional) A list of cachemodes for different disk types, e.g.
-#   ["file=directsync", "block=none"]
-#   If an empty list is specified, the disk_cachemodes directive
-#   will be removed from nova.conf completely.
-#   Defaults to an empty list
-#
-# [*libvirt_hw_disk_discard*]
-#   (optional) Discard option for nova managed disks. Need Libvirt(1.0.6)
-#   Qemu1.5 (raw format) Qemu1.6(qcow2 format).
-#   Defaults to $::os_service_default
-#
-# [*libvirt_hw_machine_type*]
-#   (optional) Option to specify a default machine type per host architecture.
-#   Defaults to $::os_service_default
-#
-# [*libvirt_inject_password*]
-#   (optional) Inject the admin password at boot time, without an agent.
-#   Defaults to false
-#
-# [*libvirt_inject_key*]
-#   (optional) Inject the ssh public key at boot time.
-#   Defaults to false
-#
-# [*libvirt_inject_partition*]
-#   (optional) The partition to inject to : -2 => disable, -1 => inspect
-#   (libguestfs only), 0 => not partitioned, >0 => partition
-#   number (integer value)
-#   Defaults to -2
-#
-# [*libvirt_enabled_perf_events*]
-#   (optional) This is a performance event list which could be used as monitor.
-#   A string list. For example: ``enabled_perf_events = cmt, mbml, mbmt``
-#   The supported events list can be found in
-#   https://libvirt.org/html/libvirt-libvirt-domain.html ,
-#   which you may need to search key words ``VIR_PERF_PARAM_*``
-#   Defaults to $::os_service_default
-#
-# [*remove_unused_base_images*]
-#   (optional) Should unused base images be removed?
-#   If undef is specified, remove the line in nova.conf
-#   otherwise, use a boolean to remove or not the base images.
-#   Defaults to undef
-#
-# [*remove_unused_resized_minimum_age_seconds*]
-#   (optional) Unused resized base images younger
-#   than this will not be removed
-#   If undef is specified, remove the line in nova.conf
-#   otherwise, use a integer or a string to define after
-#   how many seconds it will be removed.
-#   Defaults to undef
-#
-# [*remove_unused_original_minimum_age_seconds*]
-#   (optional) Unused unresized base images younger
-#   than this will not be removed
-#   If undef is specified, remove the line in nova.conf
-#   otherwise, use a integer or a string to define after
-#   how many seconds it will be removed.
-#   Defaults to undef
-#
-# [*libvirt_service_name*]
-#   (optional) libvirt service name.
-#   Defaults to $::nova::params::libvirt_service_name
-#
-# [*virtlock_service_name*]
-#   (optional) virtlock service name.
-#   Defaults to $::nova::params::virtlock_service_name
-#
-# [*virtlog_service_name*]
-#   (optional) virtlog service name.
-#   Defaults to $::nova::params::virtlog_service_name
-#
-# [*compute_driver*]
-#   (optional) Compute driver.
-#   Defaults to 'libvirt.LibvirtDriver'
-#
-# [*preallocate_images*]
-#   (optional) The image preallocation mode to use.
-#   Valid values are 'none' or 'space'.
-#   Defaults to $::os_service_default
-#
-# [*manage_libvirt_services*]
-#   (optional) Whether or not deploy Libvirt services.
-#   In the case of micro-services, set it to False and use
-#   nova::compute::libvirt::services + hiera to select what
-#   you actually want to deploy.
-#   Defaults to true for backward compatibility.
-#
-# [*log_outputs*]
-#   (optional) Defines log outputs, as specified in
-#   https://libvirt.org/logging.html
-#   Defaults to undef
-#
-# [*volume_use_multipath*]
-#   (optional) Use multipath connection of the
-#   iSCSI or FC volume. Volumes can be connected in the
-#   LibVirt as multipath devices.
-#   Defaults to $::os_service_default
-#
-class nova::compute::libvirt (
-  $ensure_package                             = 'present',
-  $libvirt_virt_type                          = 'kvm',
-  $vncserver_listen                           = '127.0.0.1',
-  $migration_support                          = false,
-  $libvirt_cpu_mode                           = false,
-  $libvirt_cpu_model                          = undef,
-  $libvirt_cpu_model_extra_flags              = undef,
-  $libvirt_snapshot_image_format              = $::os_service_default,
-  $libvirt_disk_cachemodes                    = [],
-  $libvirt_hw_disk_discard                    = $::os_service_default,
-  $libvirt_hw_machine_type                    = $::os_service_default,
-  $libvirt_inject_password                    = false,
-  $libvirt_inject_key                         = false,
-  $libvirt_inject_partition                   = -2,
-  $libvirt_enabled_perf_events                = $::os_service_default,
-  $remove_unused_base_images                  = undef,
-  $remove_unused_resized_minimum_age_seconds  = undef,
-  $remove_unused_original_minimum_age_seconds = undef,
-  $libvirt_service_name                       = $::nova::params::libvirt_service_name,
-  $virtlock_service_name                      = $::nova::params::virtlock_service_name,
-  $virtlog_service_name                       = $::nova::params::virtlog_service_name,
-  $compute_driver                             = 'libvirt.LibvirtDriver',
-  $preallocate_images                         = $::os_service_default,
-  $manage_libvirt_services                    = true,
-  $log_outputs                                = undef,
-  $volume_use_multipath                       = $::os_service_default,
-) inherits nova::params {
-
-  include ::nova::deps
-  include ::nova::params
-
-  # libvirt_cpu_mode has different defaults depending on hypervisor.
-  if !$libvirt_cpu_mode {
-    case $libvirt_virt_type {
-      'kvm': {
-        $libvirt_cpu_mode_real = 'host-model'
-      }
-      default: {
-        $libvirt_cpu_mode_real = 'none'
-      }
-    }
-  } else {
-    $libvirt_cpu_mode_real = $libvirt_cpu_mode
-  }
-
-  if($::osfamily == 'Debian') {
-    package { "nova-compute-${libvirt_virt_type}":
-      ensure => $ensure_package,
-      tag    => ['openstack', 'nova-package'],
-    }
-  }
-
-  if $migration_support {
-    include ::nova::migration::libvirt
-  }
-
-  if $log_outputs {
-    libvirtd_config {
-      'log_outputs': value => "\"${log_outputs}\"";
-    }
-  }
-
-  # manage_libvirt_services is here for backward compatibility to support
-  # deployments that do not include nova::compute::libvirt::services
-  #
-  # If you're using hiera:
-  #  - set nova::compute::libvirt::manage_libvirt_services to false
-  #  - include ::nova::compute::libvirt::services in your composition layer
-  #  - select which services you want to deploy with
-  #    ::nova::compute::libvirt::services:* parameters.
-  #
-  # If you're not using hiera:
-  #  - set nova::compute::libvirt::manage_libvirt_services to true (default).
-  #  - select which services you want to deploy with
-  #    ::nova::compute::libvirt::*_service_name parameters.
-  if $manage_libvirt_services {
-    class { '::nova::compute::libvirt::services':
-      libvirt_service_name  => $libvirt_service_name,
-      virtlock_service_name => $virtlock_service_name,
-      virtlog_service_name  => $virtlog_service_name,
-      libvirt_virt_type     => $libvirt_virt_type,
-    }
-  }
-
-  nova_config {
-    'DEFAULT/compute_driver':        value => $compute_driver;
-    'DEFAULT/preallocate_images':    value => $preallocate_images;
-    'vnc/vncserver_listen':          value => $vncserver_listen;
-    'libvirt/virt_type':             value => $libvirt_virt_type;
-    'libvirt/cpu_mode':              value => $libvirt_cpu_mode_real;
-    'libvirt/snapshot_image_format': value => $libvirt_snapshot_image_format;
-    'libvirt/inject_password':       value => $libvirt_inject_password;
-    'libvirt/inject_key':            value => $libvirt_inject_key;
-    'libvirt/inject_partition':      value => $libvirt_inject_partition;
-    'libvirt/hw_disk_discard':       value => $libvirt_hw_disk_discard;
-    'libvirt/hw_machine_type':       value => $libvirt_hw_machine_type;
-    'libvirt/enabled_perf_events':   value => join(any2array($libvirt_enabled_perf_events), ',');
-    'libvirt/volume_use_multipath':  value => $volume_use_multipath;
-  }
-
-  # cpu_model param is only valid if cpu_mode=custom
-  # otherwise it should be commented out
-  if $libvirt_cpu_mode_real == 'custom' {
-    validate_string($libvirt_cpu_model)
-    nova_config {
-      'libvirt/cpu_model': value => $libvirt_cpu_model;
-      'libvirt/cpu_model_extra_flags': value => $libvirt_cpu_model_extra_flags;
-    }
-  } else {
-    nova_config {
-      'libvirt/cpu_model': ensure => absent;
-      'libvirt/cpu_model_extra_flags': ensure => absent;
-    }
-    if $libvirt_cpu_model {
-      warning('$libvirt_cpu_model requires that $libvirt_cpu_mode => "custom" and will be ignored')
-    }
-
-    if $libvirt_cpu_model_extra_flags {
-      warning('$libvirt_cpu_model_extra_flags requires that $libvirt_cpu_mode => "custom" and will be ignored')
-    }
-  }
-
-  if size($libvirt_disk_cachemodes) > 0 {
-    nova_config {
-      'libvirt/disk_cachemodes': value => join($libvirt_disk_cachemodes, ',');
-    }
-  } else {
-    nova_config {
-      'libvirt/disk_cachemodes': ensure => absent;
-    }
-  }
-
-  if $remove_unused_resized_minimum_age_seconds != undef {
-    nova_config {
-      'libvirt/remove_unused_resized_minimum_age_seconds': value => $remove_unused_resized_minimum_age_seconds;
-    }
-  } else {
-    nova_config {
-      'libvirt/remove_unused_resized_minimum_age_seconds': ensure => absent;
-    }
-  }
-
-  if $remove_unused_base_images != undef {
-    nova_config {
-      'DEFAULT/remove_unused_base_images': value => $remove_unused_base_images;
-    }
-  } else {
-    nova_config {
-      'DEFAULT/remove_unused_base_images': ensure => absent;
-    }
-  }
-
-  if $remove_unused_original_minimum_age_seconds != undef {
-    nova_config {
-      'DEFAULT/remove_unused_original_minimum_age_seconds': value => $remove_unused_original_minimum_age_seconds;
-    }
-  } else {
-    nova_config {
-      'DEFAULT/remove_unused_original_minimum_age_seconds': ensure => absent;
-    }
-  }
-}