Update INSTALL.pipeline

INSTALL.pipeline

@@ -45,6 +45,37 @@ him know a username you'd like for yourself, if you don't already have one.
 He will set things up so your new pipeline server can coordinate with the 
 others, and will be allowed to upload finished WARCs to the Internet Archive.
 
+** STEP 2.5: PYTHON SETUP **
+
+For a recent OS, you will likely not be able to run ArchiveBot with the system
+version of Python.  One way around this is to use pyenv.  These instructions
+use the installer; we suggest reading the pyenv.run script first or installing
+it manually. For a manual installation, see <https://github.com/pyenv/pyenv>.
+
+    sudo apt install git make build-essential libssl-dev zlib1g-dev libbz2-dev \
+        libreadline-dev libsqlite3-dev libffi-dev curl
+    curl https://pyenv.run | bash
+
+Follow the directions the script gives you (probably, the shims part to add
+to .profile must be near the beginning).
+
+Restart your shell, and then:
+
+    pyenv install -v 3.6.14 # or whatever the newest python 3.6 is
+    pyenv virtualenv 3.6.14 archivebot
+    pyenv activate archivebot
+
+** STEP 2.7: TCP-CLOSER **
+
+Sometimes the pipeline clogs up due to hung sockets.  tcp-closer fixes this.
+
+    apt install cmake libmnl-dev
+    git clone https://github.com/kristrev/tcp_closer.git
+
+Follow the directions in its README.md to install.  Run as follows:
+
+    screen -dmS tcp-closer-4 -- bash -c 'sudo /usr/local/bin/tcp-closer --dport 443 -i 30 --idle_time 21601000 --last_recv_limit 43200000; exec bash'
+    screen -dmS tcp-closer-6 -- bash -c 'sudo /usr/local/bin/tcp-closer -6 --dport 443 -i 30 --idle_time 21601000 --last_recv_limit 43200000; exec bash'
 
 ** STEP 3: FINALLY, IT'S TIME TO INSTALL ARCHIVEBOT CODE **
 
@@ -198,4 +229,3 @@ If the pipeline runs out of RAM, you will likely have to kill the job
 that is consuming all the RAM; wpull instances will pause to avoid the
 OOM killer being run.  Consider creating a small swap file if your VM
 does not have any swap.
-