Done-10-10-2021

devops/01 - git/README.md

@@ -6,23 +6,110 @@
 
 * fork the current repository
 
+Done
+
 * after passing other test tasks (02 - dockerfile, 03 - docker-compose, 04 - bash, 05 - cloud-ops) need to squash all your commits to one
 
+Done
+
 * make a pull-request with the results of the tasks and tag Done-current date (e.g. `Done-01-01-2021`)
 
 
 ## Questions
 
 1. What command can I use to view the commit history?
 
-1. What command can I use to undo the last commit?
+git log
+<<<<<<< HEAD
+
+2. What command can I use to undo the last commit?
+
+git reset HEAD~1
+
+3. What command can I use to create a new branch and a new tag?
+
+git checkout -b NEWBRANCHNAME
+
+git tag -a NEWTAG
+
+4. How do I exclude a file / folder from a commit?
+
+You should to add a name of this file/folder to file .gitignore or ./git/info/exclude
+
+5. In case of a merge conflict, what commands can be used to resolve it?
+
+git status	
+
+#to see which files are unmerged
+
+git diff branch1..branch2
+
+#to see difference between branches
+
+git log branch1...branch2
+
+#to see log/commit history after making branch
+
+git reset HEAD
+
+#to cancel merge, if it will be useful
+
+git restore *
+
+#to restore all files, if it will be useful
+
+6. `*` What are pre-commit hooks and post-commit hooks, and what are they for?
+
+pre-commit - checking the correctness of the data before commit.
+
+post-commit - used to send notifications after commit.
+
+7. `*` How do I change the last commit without adding a new commit?
+
+=======
+
+2. What command can I use to undo the last commit?
+
+git reset HEAD^1
+
+3. What command can I use to create a new branch and a new tag?
+
+git checkout -b NEWBRANCHNAME
+
+git tag -a NEWTAG
+
+4. How do I exclude a file / folder from a commit?
+
+You should to add a name of this file/folder to file .gitignore or ./git/info/exclude
+
+5. In case of a merge conflict, what commands can be used to resolve it?
+
+git status	
+
+#to see which files are unmerged
+
+git diff branch1..branch2
+
+#to see difference between branches
+
+git log branch1...branch2
+
+#to see log/commit history after making branch
+
+git reset HEAD
+
+#to cancel merge, if it will be useful
+
+git restore *
+
+#to restore all files, if it will be useful
 
-1. What command can I use to create a new branch and a new tag?
+6. `*` What are pre-commit hooks and post-commit hooks, and what are they for?
 
-1. How do I exclude a file / folder from a commit?
+pre-commit - checking the correctness of the data before commit.
 
-1. In case of a merge conflict, what commands can be used to resolve it?
+post-commit - used to send notifications after commit.
 
-1. `*` What are pre-commit hooks and post-commit hooks, and what are they for?
+7. `*` How do I change the last commit without adding a new commit?
 
-1. `*` How do I change the last commit without adding a new commit?
+git commit --amend

devops/02 - dockerfile/Dockerfile

@@ -1,8 +1,12 @@
-FROM golang:1.15
+FROM golang:1.15 AS builder
 WORKDIR /usr/src/app
+RUN echo PORT=8888>./.env
 COPY main.go .
 COPY go.mod .
-COPY .env .
 RUN go get -d github.com/joho/godotenv 
 RUN CGO_ENABLED=0 GOOS=linux go build -o simple-webpage .
+
+FROM scratch
+WORKDIR /usr/src/app
+COPY --from=builder /usr/src/app/simple-webpage /usr/src/app/.env ./
 CMD ["./simple-webpage"]

devops/02 - dockerfile/README.md

@@ -12,18 +12,52 @@ You need to optimize the Dockerfile by correcting or adding steps.
 
 1. What is Docker? Which technology is it based on?
 
+Docker is an application manager with container support. It is based on the LXC technology.
+
 2. Look at the Docker file – what would you change in it?
 
+I've added Multi-staging and creating .env file inside container.
+
 3. How do I pass variables to the Docker file when building and running the container?
 
+Through the .env file.
+
 4. Why do we need multistage build ?
 
+Because we don't need golang environment in a resulting image. One container - one application.
+
 ## Tasks
 
 * Dockerfile - generate .env file inside Dockerfile, provide value of port at build step.
 
+Done
+
 * Multi-stage build – change the Dockerfile to make it multi-stage. Try to get the lowest container size.
 
+6.7 MB
+
 * Compare size of docker images with and without multistage build.
 
+without multi-staging it was 858 MB, but with this one it became 6.7 MB
+
 * Write down all commands which you have used.
+
+cat .env
+
+nano Dockerfile
+
+docker pull golang:1.15
+
+rm .env
+
+docker build -t webcounter:1.0 .
+
+docker run -d --name worker -p80:8888 webcounter:1.0
+
+docker stop worker
+
+nano README.md
+
+git add .
+
+git commit -m "02 - dockerfile"

devops/03 - docker-compose/README.md

@@ -10,38 +10,79 @@ Docker compose with 3 applications (frontend + backend + DB).
 
 ### Instructions for running
 
-1. Bootstrap the DB:
-
-`docker-compose up -d db`
-
-`docker-compose run --rm flaskapp /bin/bash -c "cd /opt/services/flaskapp/src && python -c  'import database; database.init_db()'"`
-
-2. Boot up the cluster
+1. Bootstrap the DB and boot up the cluster
 
 `docker-compose up -d`
 
-3. Browse to localhost:8080 to see the app in action.
+2. Browse to localhost:8080 to see the app in action.
 
 ## Questions
 
 1. What is the difference between Docker Compose and dockerfile? Why do I need Docker Compose?
 
+dockerfile is needed to describe how to build images, but docker compose is needed to describe how to run containers.
+
 2. How do I parameterize compose for different environments?
 
+create .env file with environment variables and use the vars from this file in docker-compose.yml file.
+
 3. What types of entities are used in docker-compose and for what purpose?
 
+version - version of docker-compose
+
+services - services/applications to start in docker containers
+
+db/flaskapp/nginx - containers names
+
+image - docker images for services
+
+volumes - volumes that storaged in docker outside containers for using inside containers
+
+env_file - file in which described environment variables to export them inside container.
+
+networks - networks in which container will have interface
+
+depends_on - services which needed to be started before starting current service
+
+command - command which will be executed after starting conatiner
+
+ports - describing port translations
+
+db_nw/web_nw - describing networks
+
+driver - selecting driver for network interfaces in used network
+
 4. `*` How to output application logs?
 
-4. `*` How to copy\upload a file from host machine to the container?
+sudo docker-compose logs SERVICE
+
+5. `*` How to copy\upload a file from host machine to the container?
 
-5. `*` How to save file changes made inside the container?
+in Dockerfile: COPY /srcPath/srcFile ./dstPath
+
+in dockercompose: volumes: - /srcPath/srcFile:/dstPath/dstFile
+
+on run: docker cp /srcPath/srcFile containerName:/dstPath
+
+6. `*` How to save file changes made inside the container?
+
+we can use volume, upload file from container to host machine, use shared folder, save container to image
 
 
 ## Tasks
 
 * Docker-compose has a bug - investigate it! What would you improve?
 
+There is a little bug with NGINX config. Also I edited Dockerfile and docker-compose.yml
+to build and run application with only "docker-compose up -d" 
+(but I added wait-for-it.sh script, recommended on docs.docker.com to make dependences between services and
+execute commands on flaskapp to create DB after database start)
+
 * Docker-compose with an environment file. Create 2 different environment files for docker-compose
 
+I added environments to docker-compose file. Now it uses env_file and .env files.
+
 * `*` Change the `docker-compose.yml` to run through dockerstack with code reuse (don't repeat yourself)
 
+I edited docker-compose.yml, so now it can work with docker-compose and docker-stack (check this with
+docker swarm with 1 host)

devops/03 - docker-compose/example/.env

@@ -0,0 +1,15 @@
+DB_TAG=9.6.5
+DB_VOLUME=dbdata
+ENV_FILE=env_file
+DB_NW=db_nw
+WEB_NW=web_nw
+FLASK_DOCKERFILE=.
+DB_DIR=/var/lib/postgresql/data
+FLASK_DIR=/opt/services/flaskapp/src
+FLASK_PORT=5432
+FLASK_CMD=bash -c "./wait-for-it.sh db:${FLASK_PORT} -- python -c 'import database; database.init_db()' && python app.py"
+NGINX_TAG=1.13.5
+PUB_PORT=8080
+NGINX_PORT=80
+SRC_CONFD=./conf.d
+NGINX_CONFD=/etc/nginx/conf.d

devops/03 - docker-compose/example/Dockerfile

@@ -8,6 +8,4 @@ RUN mkdir -p /opt/services/flaskapp/src
 COPY requirements.txt /opt/services/flaskapp/src/
 WORKDIR /opt/services/flaskapp/src
 RUN pip install -r requirements.txt
-COPY . /opt/services/flaskapp/src
 EXPOSE 5090
-CMD ["python", "app.py"]

devops/03 - docker-compose/example/conf.d/flaskapp.conf

@@ -3,11 +3,10 @@ server {
     server_name localhost;
 
     location / {
-        proxy_set_header   Host                 $host;
+        proxy_set_header   Host                 $http_host;
         proxy_set_header   X-Real-IP            $remote_addr;
         proxy_set_header   X-Forwarded-For      $proxy_add_x_forwarded_for;
         proxy_set_header   X-Forwarded-Proto    $scheme;
-        proxy_set_header Host $http_host;
 
         proxy_pass http://flaskapp:5090;
     }

devops/03 - docker-compose/example/docker-compose.yml

@@ -1,38 +1,45 @@
 version: '3'
 services:
   db:
-    image: "postgres:9.6.5"
+    image: "postgres:${DB_TAG:-9.6.5}"
+    ports:
+      - "5432:5432"
     volumes:
-      - "dbdata:/var/lib/postgresql/data"
-    env_file:
-      - env_file
+      - "dbdata:${DB_DIR:-/var/lib/postgresql/data}"
+    env_file: &environ_file
+      - ${ENV_FILE:-env_file}
     networks:
-      - db_nw
+      - ${DB_NW:-db_nw}
   flaskapp:
-    build: .
-    env_file:
-      - env_file
+    build: ${FLASK_DOCKERFILE:-.}
+    image: "${FLASKAPP_IMAGE:-example_flaskapp}:latest"
+    env_file: *environ_file
+    ports:
+      - "5090:5090"
     volumes:
-      - .:/opt/services/flaskapp/src
+      - .:${FLASK_DIR:-/opt/services/flaskapp/src}
     networks:
-      - db_nw
-      - web_nw
+      - ${DB_NW:-db_nw}
+      - ${WEB_NW:-web_nw}
     depends_on:
       - db
+    command: ${FLASK_CMD:-bash -c "
+      ./wait-for-it.sh db:5432 -- python -c 'import database; database.init_db()'
+      && python app.py"
+      }
   nginx:
-    image: "nginx:1.13.5"
+    image: "nginx:${NGINX_TAG:-1.13.5}"
     ports:
-      - "8080:80"
+      - "${PUB_PORT:-8080}:${NGINX_PORT:-80}"
     volumes:
-      - ./conf.d:/etc/nginx/conf.d
+      - ${SRC_CONFD:-./conf.d}:${NGINX_CONFD:-/etc/nginx/conf.d}
     networks:
-      - web_nw
+      - ${WEB_NW:-web_nw}
     depends_on: 
       - flaskapp
 networks:
-  db_nw:
-    driver: bridge
-  web_nw:
-    driver: bridge
+  db_nw: &bridgedriver
+    driver: overlay
+  web_nw: *bridgedriver
 volumes:
   dbdata: