Creating a Basic Google Cloud Compute Redis Instance

I use Redis for many different purposes. Sometimes, I need a large amount of RAM so Redis can act as a key store for megabytes or gigabytes of key values. Sometime I just need distributed locking and small-scale caching. Either way, setting up a Redis instance is a task I find myself performing from time to time.

Regardless of the size of the compute instance, I tend to perform the same steps: Create an Instance, select the machine type, and then under Advanced options > Automation I use a script like this:

sudo apt-get update
sudo apt-get remove man-db -y
sudo apt-get autoremove -y
sudo apt-get install -y redis-server
sudo sed -r -i 's/^bind\s+(.+?)$/# bind \1/' /etc/redis/redis.conf
sudo sed -r -i 's/^protected-mode yes$/protected-mode no/' /etc/redis/redis.conf

The basic idea is this clears out man-db and any unused packages, installs Redis, and then modifies /etc/redis.conf for my purposes. And, yes, I tend to remove man-db on my GCP instances, it really speeds up any package updating later on, especially on the smaller machine types.

Tomcat: Enabling SSL

Usually, when you get your SSL certificates, they are .crt, .key, and .ca-bundle files. These work fine for Apache’s HTTP server, but Apache’s Tomcat server needs these converted into a .jks (Java Key Store), and the Tomcat configuration set up to use that key store. To simplify the conversion, here is a shell script to perform the steps, under the assumption that the .crt, .key, and .ca-bundle files all have the same prefix.

if [ "$1" = "" ]; then
  echo ""
  echo "  usage: $0 <file-prefix> <password>"
  echo ""
  echo "  This tool requires that all files have the same prefix, and the .crt, .key, and .ca-bundle files exist."
  echo ""
  echo "  For example, if your files are named,,, you would do:"
  echo ""
  echo "    $0 mySekretPasswd"
  echo ""
  exit 1
echo ""
echo "  Generating JKS file for $1..."
echo ""
echo "----------------------------------------------------------"
openssl pkcs12 -export -in $1.crt -inkey $1.key -name $1 -out $1.p12 -passout pass:$2
keytool -importkeystore -deststorepass $2 -destkeystore $1.jks -srckeystore $1.p12 -srcstoretype PKCS12 -srcstorepass $2
keytool -import -alias bundle -trustcacerts -file $ -keystore $1.jks -storepass $2
prefix_alias=`keytool -list -v -keystore $1.jks -storepass $2 | grep -i alias | grep $1`
if [ "$prefix_alias" = "" ]; then
  echo ""
  echo "  ** something seems to have gone wrong, $1 not found in aliases"
  echo ""
  exit 1
echo "----------------------------------------------------------"
echo ""
echo "  JKS file created."
echo ""
echo "  Copy $1.jks to Tomcat's ssl directory, typically something like /etc/tomcat8/ssl/$1.jks"
echo ""
echo "  Add or Update the <Connector> entries in Tomcat's server.xml to be something like:"
echo ""
echo "    <Connector port=\"8443\" protocol=\"org.apache.coyote.http11.Http11NioProtocol\" maxThreads=\"150\" SSLEnabled=\"true\" scheme=\"https\" secure=\"true\" clientAuth=\"false\" sslProtocol=\"TLS\" keystoreFile=\"/etc/tomcat8/ssl/$1.jks\" keystoreType=\"JKS\" keystorePass=\"$2\" keyAlias=\"$1\" />"
echo "    <Connector port=\"8009\" protocol=\"AJP/1.3\" redirectPort=\"8443\" />"
echo "" 

An example of using the tool, if your certificate files all start with

./ mySekretPasswd 

Ubuntu 19.10 (and 20.04): Setting Up Time Machine

Setting up an Ubuntu machine to act as an Apple Time Machine server is surprisingly simple. This example uses a directory on the boot drive (/srv/netatalk/time-machine), but it’s more likely that you want to use a directory on a large disk.
Here are the steps…

Install the needed packages:

sudo apt install netatalk avahi-daemon

Edit the netatalk config file:

sudo vi /etc/netatalk/afp.conf

Add a section for your Time Machine:

[Time Machine]
  path = /srv/netatalk/time-machine
  time machine = yes

Create a directory to act as the Time Machine drive:

sudo mkdir -p /srv/netatalk/time-machine
sudo chown nobody:nogroup /srv/netatalk/time-machine
sudo chmod 777 /srv/netatalk/time-machine

Restart netatalk:

sudo service netatalk restart

Now, on your Mac, you should be able to open the Time Machine settings in System Preferences and use Select Disk… to pick your new Time Machine backup drive.

Update for Ubuntu 20.04 and other notes

Since I first wrote this, I have updated to Ubuntu 20.04 and everything still seems to work. However, I never made it clear that you must make sure your backup drive is available and connected on your Mac before you can use it as a Time Machine backup drive.

Once your drive is set up under Ubuntu, go to your Mac and open a Finder window. Under the Network section in the sidebar, you should see your Ubuntu machine listed. Double-click on the machine name, and you should see any shared folders on the machine. You may have to click on the Connect button in the upper right of the window to login before you can use the drive.

Once you are logged in, you should then be able to use the drive with Time Machine.

Ubuntu 19.10: File Sharing to Windows and Mac

Setting up Samba under Ubuntu 19.10 is relatively easy. This guide will show how to install Samba itself, then configure both a public drive meant to be shared among multiple users, and a per-user drive.

NOTE: This guide assumes your linux machine is on your local network.

First, install both samba and smbclient:

sudo apt install samba smbclient

Next, create a directory that will be the shared public drive, and set its ownership:

sudo mkdir -p /srv/samba/public
sudo chown nobody:nogroup /srv/samba/public
sudo chmod 777 /srv/samba/public

Now it’s time to configure Samba. There’s two basic things that need to be configured: setting the user security, and adding the public drive.

To set the user security, set security = user in the [global] section of /etc/samba/smb.conf.

Enable the per-user drive in /etc/samba/smb.conf:

    comment = Home Directories
    browseable = no
    read only = no

To add the public drive, add this section to the end of /etc/samba/smb.conf:

   comment = Public Files
   path = /srv/samba/public
   browsable = yes
   guest ok = yes
   read only = no
   create mask = 0755

Now, restart the Samba services to pick up these configuration changes:

sudo systemctl restart smbd.service nmbd.service

Since Samba doesn’t use the linux login credentials for a user, you must add each user that needs access to a shared drive using the smbpasswd command:

sudo smbpasswd -a <unix username>

Also, if you’re running a firewall on your linux machine, you’ll probably have to allow access for your local network. You can allow specific machines, or a subnet. I use ufw to control my firewall configuration, so for me I simply allowed all access for my internal network:

sudo ufw allow from

To connect to a drive from Windows, I right-click on the Network item in File Explorer and select Map network drive..., and use \\<hostname>\public or \\<hostname>\<unix username> as the Folder.

To connect to a drive from the Mac, I use Go -> Connect to Server... in the Finder, then use smb://<hostname>/public or smb://<hostname>/<unix username> as the address.