You are trying to set up kubernetes on your local machine but trying to use initialize it with kubeadmin init, returns the following error:
[init] Using Kubernetes version: v1.18.3
[preflight] Running pre-flight checks
error execution phase preflight: [preflight] Some fatal errors occurred:
[ERROR Swap]: running with swap on is not supported. Please disable swap
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher
Switch the swap to off (Ubuntu command below) and try again.
You would like to test worldPing (https://worldping.raintank.io/worldping/) in your local environment for evaluation purposes.
- Install Grafana with docker as described here (https://grafana.com/docs/grafana/latest/installation/docker/) and give it a name (ie grafana)
- Login to the grafana container and install the worldPing plugin:
$ docker exec -it grafana /bin/bash
bash-5.0$ grafana-cli plugins install raintank-worldping-app
- Exit from the container and stop and start it
$ docker stop grafana
$ docker start grafana
- Login to your grafana installation on the browser (localhost:3000) and go to the section for the plugins to find worldPing
- To be able to enable it you will need an API key from Grafana Cloud, so create a free account (https://grafana.com/signup/starter/connect-account)
- Create an API key (Security – API Keys – Add API Key)
- Go back to Grafana web UI and add the API key so you can enable the worldPing. Add an endpoint to check and select the services to check (DNS, Ping, HTTP, HTTPS)
- Leave it running for a few minutes and check the dashboards afterwards.
- Remember to Disable if you want to go back to it again in the near future, or Destroy the endpoint if you do not need it anymore.
Trying to use the usual way of adding Gitlab’s key to the ssh agent, is not working in alpine image (but it works in debian/ubuntu), and you get the following error message:
- ssh-add <(echo "$GITLABCICD_PRIVATE_KEY")
/bin/sh: syntax error: unexpected "("
Try to use the following instead:
- echo "$GITLABCICD_PRIVATE_KEY" | ssh-add -
When you create a new AWS account the access to Billing for IAM users is not enabled by default.
In order to allow access you have to follow the steps below:
- Login to your AWS account with your root user (email and password)
- Go to the top right drop down ‘My Account’
- Find the section that is called ‘IAM User and Role Access to Billing information’, use ‘Edit’, tick the box ‘Enable access’ and then ‘Update’.
More information can be found in the Amazon’s help page https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/control-access-billing.html#ControllingAccessWebsite-Activate
You would like to have a list of your subdomains for a specific domain (hosted zone), that are hosted in Amazon’s Route 53.
You can install the aws cli docker image from here https://github.com/cgswong/docker-aws if you don’t want to install the aws cli in your computer.
You can afterwards start the container with:
docker run -it cgswong/aws:latest
Then configure it by running the following and adding your credentials and zone:
efe9881d4fd:/tmp# aws configure
AWS Access Key ID [None]: aws_access_key_id
AWS Secret Access Key [None]: aws_secret_access_key
Default region name [None]: eu-central-1
Default output format [None]:
Then run the first command to get a list of the hosted zones and get the id of the hosted zone you want to find the subdomains for:
3efe9881d4fd:/tmp# aws route53 list-hosted-zones
"Comment": "HostedZone created by Route53 Registrar",
Then pick the HOSTEDZONEID and run the following to get a list of subdomains for that domain:
3efe9881d4fd:/tmp# aws route53 list-resource-record-sets --hosted-zone="HOSTEDZONEID" | grep "Name" | uniq
You would like to have a list of IPs or MAC address for the device in your network
Use the ARP protocol’s command:
$ arp -a
dv1.home (192.168.1.102) at 48:xx:xx:xx:xx:xx [ether] on wlp4s0
dv2.home (192.168.1.127) at a4:xx:xx:xx:xx:xx [ether] on wlp4s0
You would like to start using Terraform Cloud and when trying to initialize it with the new remote backend (app.terraform.io), you get the following error:
Error: Required token could not be found
Make sure you configured a credentials block for app.terraform.io in your CLI
Follow the instructions here https://www.terraform.io/docs/cloud/free/index.html and create a file ~/.terraformrc (in linux) with an API token.
You would like to check and enable the slow query log for MySQL.
To check if the log is on run the following query
show global variables like '%slow_queries'
To switch it on if the above shows it as OFF, use the following:
set @@GLOBAL.log_slow_queries = 'ON'
You would like to find out your public IP from the command line without using an online service
Use dig like the following line (taken from https://www.cyberciti.biz/faq/how-to-find-my-public-ip-address-from-command-line-on-a-linux/):
dig +short myip.opendns.com @resolver1.opendns.com
you could also add it as an alias:
alias myip=”dig +short myip.opendns.com @resolver1.opendns.com”
To get a list of all the installed crontab jobs on a server use the following (taken from https://stackoverflow.com/a/134944)
for user in $(cut -f1 -d: /etc/passwd); do echo $user; crontab -u $user -l; done